Improvements in or in connection with Photographic Shutters known as Blind Shutters.
Year: 1893

page_text: Date of Application, 2nd Aug., 1893
Complete Specification Left, 4th June, 1894-Accepted, 7th July, 1894
PROVISIONAL SPECIFICATION.
Improvements in or in connection with Photographic Shutters
known as Blind Shutters.
I, HENRY REX COOK of Fort Elizabeth, Cork, Ireland, Captain Royal
Artillery, do hereby declare the nature of this invention to be as follows :-
This invention relates to photographic shutters particularly of the character
known as focal plane blind shutters or roller blind shutters and my present
invention is as follows:-
In a suitable frame or support I arrange and mount the blind or opaque material
which constitutes the shutter in two separate parts which I shall hereinafter refer
to as the upper part and lower part respectively arranged to travel in or across n
vertical plane or thereabouts.
The lower part at its lowermost edge is permanently affixed to the lower part of
the frame while the upper edge thereof is attached to a bar or other device
(extending across the aperture controlled by the blind) and free to move up and
down in a recess or other suitable guide-way at each side of the frame.
The blind or opaque material of this lower part may be formed so as to fold and
expand like a "bellows" or may be arranged and mounted in any other suitable
way so long as it is capable of being drawn out to its full length and readily re-fold
or stow itself away on being released.
A suitable lifting device (knob handle cord chain or connection) so arranged
and mounted in connection with the aforesaid bar or other device extending across
the blind aperture that this lower part can be thereby raised right across the
aperture controlled by this said blind.
Also this said travelling. bar has affixed thereto a cord or cords or other
connection attached to a drum or barrel containing a coiled or other suitable spring
so that when this said bar is raised the barrel is revolved and thereby the spring is
wound up and pressure is thereby exerted to draw down this lower blind.
The upper part (or upper blind) also arranged to travel up and down in a
similar manner only in this case the top edge is permanently connected to the top
or upper part of the frame while the lower or free edge has a bar or other
device travelling in the same or corresponding recesses or guide-ways at the sides
of the frame while the opaque material (forming this upper blind) folds up bellows
fashion or in other suitable way as desired.
The bar or other device on the lower edge of this upper part is attached by
cords or other suitable connections to pulleys or drums fixed on an axle to which
latter the inner end of the aforesaid coiled spring is attached-these cords or
connections to the upper blind being wound upon said pulleys in the opposite
direction to that in which the cords on the lower blind are wound on the aforesaid
spring drum so that the spring is thus wound up from both ends simultaneously
as hereinafter further explained.
I also may provide means for independently winding up and unwinding this
spring (or springs) for actuating these separate parts of the shutter so as to thereby
vary the rapidity of travel of same as desired.
The aforesaid two separate bars or devices on the travelling edges of the upper
and lower blinds are so formed or mounted as to form a light-tight joint between
them when pressed or laid together.
To set the shutter the said raising device controlling the lower bar is actuated
80 as to cause the lower bar to move from its lowermost position to the highest
position and as the bar on the upper part lies in the path of this lower bar

page_text: same is thereby simultaneously raised with the lower bar and while the upper
blind (or upper part) now becomes folded or moved out of the way of the lower
part (or lower blind) takes its place across the blind aperture and a spring catch
or other suitable holding and releasing device now engages the said lower part
as well as the upper part so as to hold same in position ready for giving an
exposure and in moving these two parts upward they remain light-tight while
the lower part at the same time has wound the spring from the outer end thereof
the upper part has wound the spring from the inner end thereof and consequently
this actuating spring has now a steady and equal pull on both parts to draw same
down when released.
By turning or moving the releasing catch the lower part only is released and
moves rapidly downwards thus giving the exposure while at any desired moment
after the release of the lower part the upper part is subsequently released and
immediately falls in the path of the lower part this action closing the aperture
after the exposure.
By this means an exposure of any desired duration may be given from the most
instantaneous to the most lengthened exposure desired-and for the purpose of
timing and accurately regulating the duration of such exposure any suitable
regulating apparatus may be used for instance a pneumatic retarding device
capable of offering varying degrees of resistance such as are now well known in
certain photographic shutters.
It will be obvious that this shutter is capable of modifications in several ways
without departing from the nature of my said present invention for instance the
lower edge of the lower blind might be attached direct to the aforesaid spring
barrel or roller controlled by a spring so that on raising this said lower part as
aforesaid the blind would be unwound off this spring barrel or roller actuated by a
spring so that the spring would be wound up the operation being identical as
before described.
Also if desired the lower part may actuate a spring barrel or roller controlled by
a spring independent of the spring controlling the upper blind but in practice it
will be found advantageous to use the one spring wound from both ends as before
described for the reason that the one spring acting on both of the separate blinds
the pull or strength exerted on each will always be constant and consequently the
upper blind would not be liable to overtake the lower blind when giving an
exposure unless this should be desired.
A further obvious modification would be to have the upper blind wound on a
roller (instead of acting bellows fashion) if desired.
This shutter may be made to work on its side or in any desired position instead
of vertically as may be required, and may be arranged and mounted and used for
photographic purposes in any suitable manner desired either separately mounted or
built into the photographic apparatus with which it is to be used.
Dated this 2nd day of August 1893.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or in connection with Photographic Shutters
known as Blind Shutters.
1, HENRY REX COOK of Fort Elizabeth, Cork, Ireland, Captain Royal
Artillery, 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 photographic shutters of the character known as roller

page_text: blind shutters for use as desired for instance as focal plane blind shutters or in any
other suitable manner for which same may be applicable.
In photographic shutters as at present usually constructed for photographic
cameras there is no means of preventing the exposure of the lens or sensitive plate
while the blind is being raised except by having an additional blind usually called
a "safety blind." Further in shutters of the type known as focal plane shutters
there is no simple method of altering the size of the slit in the blind from outside
without touching the interior arrangements.
Now my present invention is designed with the object of constructing a blind
shutter which can be set without exposing the lens or sensitive plate and when used
as a focal plane shutter readily permits either increasing or diminishing the size of
the opening (passing across the front of the sensitive plate) from outside the
camera or shutter.
My invention consists essentially in constructing the shutter with the blind made
in two parts working (i.e. moving) in or about the same plane both of which are
advantageously worked by one and the same spring. When the shutter is being
set the lower part is pulled or pressed against the upper blind thus raising both
simultaneously one part is caused to overlap the other somewhat in order to prevent
the passage of light between them (or some similar means) while the shutter is
being set.
When it is desired to make an exposure the lower blind is released and uncovers
the lens or sensitive plate and the release of the second or upper blind which
follows in the path of the first terminates the exposure.
It is obvious that if the
mechanism governing the release of the two parts be suitable one may be made to
follow the other at any given interval.
Thus any exposure from the very shortest to the most prolonged may be given
at will.
According to my present invention :--
In a suitable frame or support. I arrange and mount the blind or opaque material
which constitutes the shutter in two separate parts which I shall hereinafter refer
to as the "upper part" and the "lower part" respectively arranged to travel in or
across a vertical plane or thereabouts.
The lower part at its lowermost edge is permanently affixed to the lower part of
the frame or it may be a lower roller while the upper edge thereof is attached to a
bar or other device (extending across the aperture controlled by the blind) and free
to move up and down in a recess or on guide wires or equivalent or other suitable
guideway at each side of the frame.
The blind or opaque material of this lower part may be formed so as to fold and
expand like a "bellows " or be wound upon a roller or may be arranged and
mounted in any other suitable way so long as it is capable of being drawn out to its
full length and readily re-fold re-wind or stow itself away on being released.
A suitable lifting device (knob handle cord chain or connection) is so arranged
and mounted in connection with the aforesaid bar or other device extending across
the blind aperture that this lower part can be thereby raised (or moved) right
across the aperture controlled by this said blind.
Also this said travelling bar has affixed. thereto a cord or cords or other
connection attached to a drum or barrel containing a coiled or other suitable spring
so that when this said bar is raised the barrel is revolved and thereby the spring is
wound up and pressure is thereby exerted to draw down this lower blind-or instead
thereof the spring may be combined with the aforesaid roller if used to wind the
lower part thereon.
The upper part (or upper blind) is also arranged to travel up and down in a
similar manner only in this case the top edge is permanently connected to the top
or upper part of the frame (or may be mounted on a roller or in other equivalent
manner) while the lower or free edge has a bar or other device travelling in the
or corresponding recesses or guideways (as those for the lower blind.
same
.

page_text: aforesaid) at the sides of the frame while the opaque material (forming this upper
blind) folds up bellows fashion or is wound upon a roller or in other suitable way
as desired.
The bar or other device on. the lower edge of this upper part is attached by
cords or other suitable connections to pulleys or drums fixed on an axle to which
latter the inner end of the aforesaid coiled spring is attached-or it may be an
independent spring-these cords or connections to the upper blind being wound
upon said pulleys in the opposite direction to that in which the cords on the lower
blind are wound on the aforesaid spring drum so that the spring is thus wound up
from both ends simultaneously as hereinafter further explained or in any other
equivalent or suitable manner.
10°
I also may provide means for independently winding up and unwinding this
spring (or springs) for actuating these separate parts of the shutter so as to thereby
vary the rapidity of travel of same as desired.
upper
The aforesaid two separate bars or devices on the travelling edges of the.
and lower blinds are made to overlap or otherwise formed or mounted as to form a
light-tight joint between them when pressed or laid together-while setting the
shutter.
To set the shutter the said raising device controlling the lower bar is actuated so
as to cause the lower bar to move from its lowermost position to the highest position
and as the bar on the upper part lies in the path of this lower bar same is thereby
simultaneously raised with the lower bar and while the upper blind (or upper part)
now becomes folded or rolled up or otherwise moved out of the way of the lower
part (or lower blind) and takes its place across the blind aperture and a spring
catch or other suitable holding and releasing device (which may be independent
catches for each part) now engages the said, lower part as well as the upper part so
as to hold same in position ready for giving an exposure and in moving these
two parts upward they remain light-tight while the lower part at the same time
has wound the spring from the outer end thereof the upper part has wound the
spring from the inner end thereof and consequently this actuating spring has now
a steady and equal pull on both. parts to draw same down when released.
By turning or moving the releasing catch the lower part only is first released and
moves rapidly downwards, thus giving the exposure while (by suitable means) at any
desired moment after the release of the. lower part the upper part is subsequently
released and immediately falls in. the path of the lower. part this action, closing the
aperture after the exposure.
By this means an exposure of any desired duration may be given from the most
instantaneous to the most, lengthened exposure desired-and for the purpose of
timing and accurately regulating the duration of such exposure any suitable
regulating apparatus may be used for instance a pneumatic retarding device capable
of offering varying degrees of resistance such as is now well known in certain
photographic shutters.
It will be obvious that this shutter is capable of modifications in several ways
without departing from the nature of my said present invention for instance the
lower edge of the lower blind might be attached direct to the aforesaid spring barrel
or roller controlled by a spring so that on raising this said lower part as aforesaid
the blind would be unwound off this spring barrel or spring roller so that the
spring therein or thereon would be wound up the operation being identical as before
described.
Also if desired the said lower part may actuate a spring barrel or roller controlled
by a spring independent of the spring controlling the upper blind but in practice it
will be found advantageous to use the one spring wound from both ends as before
described for the reason, that the one spring acting on both of the separate
blinds the pull or strength exerted on each will always be constant and
consequently the upper blind would not be liable to overtake the lower blind
when giving an exposure unless this should be desired as for instance when less

page_text: exposure is required to be given to the lower part of the plate when means
for checking the lower blind and thus allowing the upper blind to overtake it
may be used.
A further obvious modification would be to have the upper blind wound on a
roller instead of acting bellows fashion-as aforesaid.
This shutter may be made to work on its side or in any desired position (instead
of vertically) as may be required and may be arranged and mounted and used for
photographic purposes in any suitable manner desired either separately mounted or
built into the photographic apparatus with which it is to be used.
And in order that my present invention may be easily understood and readily
carried into practice I will proceed to further describe same with reference to the
drawings hereunto annexed.

page_text: -coming down too far and also to lead the cords G¹Gʻ down in the same plane (more
or less) as the blind C.
The operation is as follows.
When the shutter is to be set the tassel etc. in which the strings K' K' terminate
is pulled. This raises the bar J and the lower part C which presses against the 5
upper part B and both are raised until the said catches thereon engage with the said
triggers. At the same time the barrel Y is caused to revolve by the cord connected
with K' K' until the catch on Y engages with and is held by the trigger M.
When the trigger M is pressed the lower part C is released and is pulled down by
the cords H H attached to the barrel L as in Fig. 1 or is wound up on the barrel
as in Fig. 3.
°
The barrel Y is also released and revolves until the arm P clamped to it strikes
the trigger N which releases the upper part B which is pulled down by the
cords G G attached to the pulleys D₁ D' revolving in the opposite direction to
the barrel L.
The arm P may be clamped so as to strike earlier or later against the trigger N
so that the release of the second trigger may be varied at will.
Any other suitable means of releasing the two parts B and C may be adapted such
as a pneumatic or other releasing device.
Referring now to Sheet 2 :-
Fig. 1 represents a shutter for use on the lens in which both parts of the blind
are wound on rollers and
3
Fig. 2 is an edge view thereof with the side removed.
Fig. 3 is a vertical section on line 1-1 Fig. 1.
Fig. 4 is view of opposite side to Fig. 1 the case being removed in each view.
A is the case.
B is the upper part of the blind fixed to the roller R.
C is the lower part of the blind fixed to a barrel L.
D¹ D are rollers or drums fixed to the axle I.
E and F are stops to prevent the blinds descending too far. They have holes in
them to guide the strings G¹ G².
E and F are pivotted to the case and are free to rise and fall vertically to
a small extent.
G'G' are cords connecting the upper part B with the rollers D¹ D' and are
attached to the spreader or transverse bar I.
K' K are cords (attached to the spreader or transverse bar J of the lower
part C) which pass over the roller R and down to the bottom of the case and meet.
in a tassel or equivalent on the exterior of the case.
M is a releasing bar which releases the spring catches Q'Q' which engage in
the detent 00' on the axle T (see especially the detailed sectional view Fig. 5,
Fig. 6 which shows an exterior side elevation and Fig. 7 showing inside of case).
N is a catch which engages with the catch V on the lower part C.
Pis a bar which slides up and down in the block H and engages in a detent or
-tooth on the roller R.
P is pivotted to the stop E and rises and falls with it.
U is a bent (spring) lever which on being pressed into the case A prevents the
stop E from falling.
The operation is as follows:-
To set the shutter the tassel is pulled the cords K₁ K' connected with the lower
part C tighten on the pulleys at each end of roller R and the lower part C being
thereby pressed against the upper part takes it up with it.
The barrel L is moved round in one direction and the axle T with the
pulleys D' D' in the opposite direction (and so the spring S is wound) as the curtain
and cords are respectively unwound off them. The friction of the cords K' K' on
the roller R is sufficient to turn same round when the pressure of the main spring
on the upper part B is eased by the pressure of the lower part C and so as to roll
up the blind B on the roller R.

page_text: The upper part is thus wound on to the roller R and the lower part is wound off
the barrel L. At the same time the main spring S is wound up by the barrel
turning one way and the axle in the other. The strain on the cords G¹ G' is
sufficient to raise the stops E and F. When the stop E is raised the arm P is also.
raised until when the two blinds are raised to the topmost position the arm P
engages with the catch on the roller R and thus prevents the descent of the
upper part B.
Also the catch V engages with the trigger or release N. When the release N is
pulled out the part C descends until it strikes the stops E and F which are thus
depressed. When E is depressed the arm P is moved downwards and the roller R.
is thereby released and the upper part B then descends.
The time arrangement U is contrived so that when desired it is connected with
the trigger N and when the latter is pulled or moved out the lower end of the bent.
lever U is pressed in under the stop E and so long as the trigger N is kept out the
stop E is prevented from falling and consequently the upper part B remains steady
until the trigger N and lever U return to the first or normal position when the
bar J forces down E thereby drawing down P out of engagement with R and
consequently the upper part B now rapidly descends.
$
Fig. 2 showing the side view also shows the catches Q¹ and Q. Q' Fig. 2 is a
spring pressing against the detent teeth O on the axle-Q' is fixed to the pulley D!.
When the blind is set the spring in the barrel can be further wound up by twisting
the axle T. The teeth on the axle engaging with the spring on the pulley
permit the axle to be wound one way but not the other. When it is desired to.
release the tension on the main spring S the release M is pressed in and while the
shutter is being set the pulleys D' D' revolve until the end of the springs QQ
touch the release M which thus releases the spring Q'Q' from the teeth O'O' on.
the axle which is then free to run down.
Referring now to Sheet 3 :-
Fig. 1 Sheet 3 represents a focal plane blind shutter in which also both parts of
the blind are mounted on rollers.
Fig. 2 is an edge view in sectional side elevation.
Figs. 3 to 6 are local views showing details of construction.
A is the case.
B is the upper part of the blind mounted on the roller R which is free to revolve
on its axle.
C is lower part of the blind mounted on a spring barrel or roller having the
mainspring therein.
D' D' are pulleys fixed to the axle on which the barrel of the lower part of the
blind revolves.
FF are stops.
GG are cords connecting the upper part B with the pulleys D¹ D'.
K'K' are cords connecting the lower part C with pulleys E¹ E which are firmly
fixed to an axle which is mounted so as to be free to revolve in the sides of the
case A and on which roller R in its turn is free to revolve.
Kis fixed to the pulley E' and is continued until it passes out of the bottom of
the case and terminates in a tassel or other suitable means for grasping.
His a cord fixed at one end to the roller R and is wound on it the opposite way
to the part B so that winding up B unwinds the cord H and vice versa.
H passes through an eye or guide on K¹ on the outside of the case A and
terminates in a tassel etc.
N is a catch which engages with a detent on the roller R. It is of the
shape shown in Fig. 4 and is pivotted in the case A one arm being inside and
the other outside.
P is an arm which can be clamped on to the axle by the nut T.
The operation is as follows :--
To set the shutter the tassel on K' is pulled this also pulls the cord H.
The pulleys El E² are caused to revolve and the nort
vised
The nant
R

page_text: is also raised and is wound on to the roller R. When the two parts reach the
topmost position the catch N is raised by the bars I and J until it engages with the
detent on R as shown in dotted lines in the local view of the parts in Fig. 5.
When the lower part C is allowed to fall the pulleys E' E' revolve and the axle
connecting them and carrying the arm P and nut T also revolves. The arm P is
carried round until it strikes the outside arm of the catch N which being depressed
releases the roller R and the upper part B is now free to descend.
For focussing purposes the part B may be raised by pulling the cord H the
part C remaining at rest in the lowermost position.
When desired the upper part B may be released by touching the trigger N.
Q spring catch and pneumatic release is shown on the left of Fig. 1.
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 known as blind shutters-arranging
and constructing the blind in two separate parts of flexible light-tight material
(without any aperture in either) both said parts being adapted to travel in the same
plane and in such manner that by pulling on the one part same overlaps and acts
upon the other to thus set the shutter.
2. In photographic shutters of the character known as blind shutters-arianging
and constructing the blind in two separate parts of flexible light-tight material
(without any aperture in either) both said parts being adapted to travel in the same
plane and in such manner that by pulling on the one part same overlaps and acts
upon the other to thus set the shutter with means to independently retain and
successively release the said two parts so that the opening to give the exposure is
obtained by this variation in the release.
3. In photographic shutters of the character known as blind shutters-forming
the blinds in two separate parts of flexible light-tight material (without any
aperture in either) both adapted to travel in the same plane and arranged and
acting in such a manner that the first part of the blind is released while the second
part is retained and the latter subsequently released, the opening to give the
exposure being thus obtained by this variation in the release of the said two
parts.
4. In photographic shutters of the character known as blind shutters-the
combination with a blind arranged in two separate parts without any aperture in
either and respectively mounted on opposite sides of the aperture through which
the exposure is given and both adapted to travel in the same plane of means to
draw or move one such part across the lens aperture which first part is adapted to
engage with and overlap the second part which is thereby also caused to travel
to set the shutter without admitting light to the sensitive surface means to
independently retain each such part when set and means to enable the release of
the first said part alone before the second said part is released and means for the
first said part during its travel to release the second said part this variation in the
release thus causing an opening between the two parts of the blind and allowing
the exposure to take place substantially in the manner and for the purposes
herein before set forth.
5. In photographic shutters of the character known as blind shutters-the
arrangement of the blind in two separate parts without any aperture in either one
such part being mounted to fold or roll up on one side of the aperture through which
the exposure is given and the other part of said blind mounted to fold or roll up on
the opposite side of said aperture in combination and acting in conjunction with
each other and with independent means to retain each such part when set means to
first release only one part of the blind and means to subsequently release the second
part at any desired moment the blind being set the opening for the exposure being
obtained by the variation in the release and the whole shutter operating
substantially in the manner and for the purposes hereinbefore set forth.

page_text: 6. In a photographic roller blind shutter-the arrangement and combination.
therewith of a spring roller the motor spring of which is adapted to be wound from
cach end thereof in opposite directions to control two separate roller blinds or two.
separate parts forming one blind and either with or without means to independently
wind up or unwind said spring to vary its strength substantially in the manner and
for the purposes herein before set forth.
7. A photographic blind shutter having the blind formed in two parts such as B
and C both travelling in the same plane and mounted arranged and acting in
combination with each other and with the other parts to form a shutter-
substantially in the manner and for the purposes hereinbefore described with.
reference to and as illustrated in Figs. 1 and 2 of Sheet 1 of the drawings hereunto
annexed.
8. A photographic blind shutter having the blind formed in two parts such as B
and C both travelling in the same plane and mounted arranged and acting in
combination with each other and with the other parts to form a shutter
substantially in the manner and for the purposes herein before described with
reference to and as illustrated in Figs. 3 and 4 of Sheet 1 of the drawings hereunto.
annexed.
9. A photographic blind shutter having the blind formed in two parts such as B
and C both travelling in the same plane and mounted arranged and acting in
combination with each other and with the other parts to form a shutter substantially
in the manner and for the purposes herein before described with referenceito and as.
illustrated in Sheet 2 of the drawings hereunto annexed.
10. A photographic blind shutter having the blind formed in two parts such as B.
and C both travelling in the same plane and mounted arranged and acting in.
combination with each other and with the other parts to form a shutter substantially
in the manner and for the purposes hereinbefore described with reference to and as
illustrated in Sheet 3 of the drawings hereunto annexed.
11. Photographic blind shutters arranged constructed combined and acting
substantially in the manner and for the purposes hereinbefore described and
illustrated in the drawings hereunto annexed.
Dated this 2nd day of June 1894.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.