Improvements in or relating to Photographic Blind Shutters.
Year: 1895

page_text: PROVISIONAL DI MUITIALIN
Improvements in or relating to Photographic Blind Shutters.
LODEWYK JAN RUTGER HOLST, of 90 Damrak, Amsterdam in the Kingdom
of The Netherlands, Engineer, do hereby declare the nature of this invention to be
as follows:
The objects of this invention are, first, to provide a blind shutter capable of
giving both instantaneous and time exposures at pleasure without the slightest
alteration at the camera; second, to arrange the blind shutter for easily altering
the width of the slit for instantaneous exposures; and third, to employ a device
for causing the width of the said slit to either remain constant during the
running-off, or to continually increase or decrease respectively. In the last case.
the sensitive plate will be less exposed for the sky than for the rest.
The blind consists in two separate portions, which are made to run off either.
together for instantaneous exposures or one after the other for time exposures..
The frame of the blind shutter may be a part of the photographic camera, or it
may be self-contained and arranged for in in the camera.
a,
Near the bottom of the frame two shafts, hereinafter called "B" and "F," are
placed, which work together by means of two equal gear wheels and carry two
loose spring barrels, hereinafter called "C" and "G," revolving in opposite
directions. One of the shafts, say B, carries on the outside a kuob for turning
both shafts with the hand and thereby stretching the springs in the barrels, also
ratchet wheel, into which a spring-pressed pawl at the frame gears to check the
shafts. The one barrel C is arranged to wind on the first blind portion and after
this two strips attached thereto and hereinafter called "W!". The other barrel G
is in a similar manner arranged to wind on cords and thereby stretch out the
second blind portion attached thereto..
Near the top of the frame two shafts, hereinafter called "N" and "Q," are
placed, which may work together by means of two equal gear wheels, hereinafter
called "U" and "V." The gear wheel V is fixed on the shaft .N, while the
other U is fastened on the long boss of a loose disk on the shaft Q. Besides the
loose disk on the outside of the frame a movable claw wheel having claws on both
sides is mounted on the shaft Q aud prevented by some means from turning. The
claw wheel is pressed by a spiral spring against the loose disk and has a pin to engage
in one of several holes provided in the latter. Then the gear wheel U is thereby
coupled with the shaft Q, so that the two shafts N and Q work together. At the
end near the claw wheel the shaft Q carries a knob for turning it with the hand.
On the knob a spring-pressed catch is so arranged, that it snatches the claw wheel
on moving the latter out of engagement with the loose disk. Then the gear
wheel U is disconnected from its shaft Q, so that the two shafts NQ no longer
work together. On the shaft N two fast drums, hereinafter called "W," and
between them a long loose drum, hereinafter called "L," are mounted.. The
shaft N carries at the one end a knob for turning it with the hand, so that either it
alone revolves, or both shafts NQ revolve in opposite directions, if the gear
wheel U is coupled with its shaft Q in the manner described above. On turning
the shaft. N in one direction the two fast drums, W wind on the strips W₁ and
thereby raise the first blind portion, so that the spring inside the barrel C is

page_text: stretched. On releasing the shaft N, the first blind portion drops, when the
sensitive plate will be exposed. To the loose drum L two gear wheels, hereinafter
called "M" and "M'," are fixed, which gear into corresponding gear wheels on
the shaft Q and hereinafter called "P" and "P1" respectively. The two gear
wheels PM working together have the same diameter, while the other gear
wheels PM are different in size. Means are provided, whereby either the
gear wheel P or the other P1 may be coupled with the shaft Q. The second blind
portion is fastened to the long loose drum L, so that the latter when revolving in
one direction will wind on and thereby raise the former. At the same time the
cords attached to the second blind portion are unwound from the spring barrel G,
whereby the spring in the latter will be stretched. On releasing the drum L this
spring therefore will quickly wind on the cords again, so that the second blind
portion drops and is stretched out.
When the gear wheel U is coupled with its shaft Q and either of the two
shafts NQ is turned, both the fast drums W and the loose drum L revolve, so
that the two blind portions are raised or lowered together. If the drum Lis
moved from the shaft Q through the equal gear wheels P M, the width of the slit
between the two blind portions will remain the same during the raising and the
dropping. If on the other band the drum L is moved from the shaft Q through
the unequal gear wheels P¹ M', the width of the slit will increase or decrease
respectively during the running-off and vice-versa during the raising of the blind.
The width of the slit, which is preferably made like the height of the sensitive
plate, can be made narrower in the manner, that first the claw wheel is disengaged
from the loose disk, so as to disconnect the gear wheel U from its shaft, then the
shaft N is turned to raise the first blind portion alone, until the required width of
the slit is attained, and afterwards the claw wheel is again put into gear with the
loose disk, so as to couple the gear wheel U with the shaft Q. In this case,
however, the spring in the barrel C attains a greater tension than that in the other
barrel G. On releasing the blind the barrel C would for this reason not stop yet,
when the other barrel G has already unwound the second blind portion from its
drum Land stretched it out, but the drum L would continue to revolve and again
wind on the second blind portion and this time in the opposite sense. Then
the sensitive plate would be more or less again exposed, which of course is not
intended. I therefore provide for a ratchet wheel fixed to the spring barrel G and
a spring-pressed pawl gearing thereto, so as to check this barrel, after it has
stretched out the second blind portion. I also employ a key for moving this pawl
out of gear with the ratchet wheel, so as to release the spring barrel G for the
purpose of setting the blind shutter.
Outside on the frame a fork is placed, which can be brought into either of two
positions. In the one position the one arm of the fork engages with the outer
claws of the claw wheel, while in the other position of the fork its other arm
engages with the inner claws of the claw wheel. The fork is made in two parts
linked together in the manner, that the top part engaging with the claw wheel can
be moved off from the frame and thereby either release the claw wheel or shift it
out of engagement with the loose disk. Between the fork and the frame a pocket
is placed, which is capable of being inflated or blown up, so as to move the fork off
from the frame. The pocket is put in communication through a hose with a
common hand ball, which latter is pressed to blow up the pocket. A spring is
employed to press the top part of the fork back and against the frame on releasing
the hand ball, when the pocket is no longer blown up.
For instantaneous exposures the blind shutter is worked in the following manner :
The pawl checking the spring barrel G is moved out of gear with the ratchet
wheel by means of the key, then the slit between the two blind portions is made
the required width, whereupon the gear wheel U is coupled with its shaft Q by
putting the claw wheel into gear with the loose disk, and afterwards the fork is
brought into the one position, in which its one arm engages with the outer claws
of the claw wheel. At the proper moment the hand ball is pressed to inflate the

page_text: pocket, which in its turn moves the fork off and thereby releases the claw wheel,
when both blind portions will drop.
For time exposures the fork is brought into the other position in which its other
arm engages with the inner claws of the claw wheel. Then the two blind portions
are raised until the first one is quite stretched out. At the proper moment the
hand ball is pressed to blow up the pocket, which in its turn moves the fork off
and thereby shifts the claw wheel out of engagement with the loose disk. Then the
shaft N is released and the first blind portion alone drops, so that the sensitive
plate is exposed. The pocket being still blown up and the fork engaging with the
claw wheel, the shaft Q remains idle, while the claw wheel has been snatched by
the catch. When the exposure is finished, the hand ball is released, whereupon
the fork is pressed back against the frame and the claw wheel is released, when the
second blind portion drops.
Dated this First day of March 1895.
Improvements in or relating to Photographic Blind Shutters.
:
I, LODEWYK JAN RUTGER HOLST, late of 90 Damrak and now of 259
Heerengracht, Amsterdam in the Kingdom of The Netherlands, Engineer, 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 objects of this invention are, first, to provide a blind shutter capable of giving
both instantaneous and time exposures at pleasure without the slightest alteration
at the camera; second, to arrange the blind shutter for easily altering the width of
the slit for instantaneous exposures; and third, to employ a device for causing the
width of the said slit to either remain constant during the running-off, or to
continually increase or decrease respectively. In the last case the sensitive plate
will be less exposed for the sky than for the rest.
In order that my invention may be fully understood and readily carried into
effect I will now proceed to describe the two sheets of drawings accompanying
this my complete Specification, having reference to the figures and letters marked
thereon.
Fig. 1 is a vertical cross section of the apparatus, taken in the plane of the
line a-b in Fig. 3; Fig. 2 is a front view of the same;
-fin
Fig. 3 is a vertical longitudinal section taken in the plane of the line e-.
Fig. 5;
Fig. 4 is a side view taken from the right hand in Fig. 2;
Fig. 5 is a horizontal sectional view taken in the plane of the line c-d in
Fig. 3; finally
Fig. 6 and 7 are side views taken from the left hand in Fig. 2.
The blind consists in two separate portions Y and K, which are made to
run off either together for instantaneous exposures or one after the other for time
exposures.
The frame A of the blind shutter may be a part of the photographic camera, or
it may be self-contained and arranged for inserting in the camera.
Near the bottom of the frame A two shafts B and F (Fig. 1) are placed, which
work together by means of the two equal gear wheels D and E and carry the two
loose spring barrels C and G, revolving in opposite directions. One of these shafts,
say B, carries on the outside a knob Z for turning both shafts with the hand and
thereby stretching the springs in the barrels, also a ratchet wheel Z', into which a
spring-pressed pawl Z' at the frame A gears to check the shafts. The loose spring

page_text: Barrels C and G enclose spiral springs (see F¹ in Fig. 3), each of which is fixed at
the one end to the shaft and at the other end to the barrel. Of course the spiral
springs are so arranged, that the two barrels C and G revolve in different seuses,
when the blind after setting is released. The one barrel C is arranged to wind on
the first blind portion Y and after this the two strips WW attached thereto.
The other barrel G is in a similar manner arranged to wind on the cords H H and
thereby stretch out the second blind portion K attached thereto. The edges of the
two blind portions Y K are each stiffened by a bar X and I respectively.
Near the top of the frame A two shafts Ň and Q are placed, which may work
together by means of the two gear wheels U and V having the same diameter. The
gear wheel V is fixed on the shaft N, while the other U is fastened on the long
boss of the loose disk T on the shaft Q. Besides the loose disk T on the outside
of the frame A a movable claw wheel S having claws S¹ S¹ on both sides is mounted
on the shaft Q and is prevented by some means from turning, say by means
of a feather as shown in Fig. 5. The claw wheel S is pressed by a spiral
spring R against the loose disk T and has a pin S² to engage in one of
several holes provided in the latter. Then the gear wheel U is thereby
coupled with the shaft Q, so that the two shafts N and Q work together. At
the end near the claw wheel S the shaft Q carries a knob R for turning it
with the hand. On the knob R a spring-pressed catch R' is so arranged, that it
snatches the claw wheel S on moving the latter out of engagement with the loose
disk T. Then the gear wheel U is disconnected from its shaft Q, so that the two
shafts NQ no longer work together. On the shaft N two fast drums W W and
between them a loug loose drum L are mounted. The shaft N carries at the one
end a knob O for turning it with the hand, so that either it alone revolves, or both
shafts NQ revolve in opposite directions, if the gear wheel U is coupled with its
shaft Qin the manner described above. On turning the shaft N in one direction
the two fast drums W W wind on the strips W₁ W₁ and thereby raise the first
blind portion Y, so that the spring inside the barrel C is stretched. On releasing
the shaft N, the first bliud portion Y drops, when the sensitive plate (on the left
side of the frame A in Fig. 1) will be exposed. The second blind portion K is
made narrower than the first one Y, so as to keep it free from the strips W1 W¹.
To the ends of the loose drum L the gear wheels M and M' are fixed, which gear
into the loose gear wheels P and P¹ respectively. The latter are mounted on the
shaft Q and are provided with claws P2 and P3. The two gear wheels P M working
together have the same diameter, while the other gear wheels P' M' are different
in size. Between the two gear wheels P P¹ a movable sleeve Q' having claws Q³
and Q at the ends is put on the shaft Q and prevented by the key from
turning. In the top of the frame A a shaft Q' carrying a crank Q8 outside and an
eccentric pin Q inside is mounted. By turning the crank Q8 from right to left
the eccentric pin 0° engaging in the groove Q of the sleeve Q' is caused to shift
the latter in the same direction, so that the claws Q3 are put into gear with
those P2 of the gear wheel P. This position of the sleeve Q₁is shown in Figs. 3
and 5, in which case the gear wheel P is coupled with the shaft Q. If the crank Q
is brought into the middle position, the claws Q3 of the sleeve Q' are put out of
gear with those P2. Then the two wheels P P are both disconnected from the
shaft Q. In a similar manner by turning the crank Q8 further to the right the
other gear wheel P1 may be coupled with the shaft Q.
The second blind portion K is fastened to the long loose drum L, so that
the latter when revolving in one direction_will wind on and thereby raise
the former. At the same time the cords H H attached to the second blind
portion K are unwound from the spring barrel G, whereby the spring F in the
latter will be stretched. On releasing the drum L this spring therefore will
quickly wind on the cords H H again, so that the second blind portion K drops and
is stretched out.
When the gear wheel U and one of the gear wheels P P¹ are coupled with the
shaft Q and either of the two shafts N Q is turned, both the fast drums W W and

page_text: the loose drum L revolve, so that the two blind portions Y K are raised or lowered
together. If the drum L is moved from the shaft Q through the equal gear
wheels P M, the width of the slit between the two blind portions Y K will remain
the same during the raising and the dropping. If on the other hand the drum L
is moved from the shaft Q through the unequal gear wheels P¹ M' the width of
the slit will increase or decrease respectively during the running-off and vice-versa
during the raising of the blind. The width of the slit, which in general is prefer-
ably made like the height of the sensitive plate, can be reduced in the manner, that
first the claw wheel S is disengaged from the loose disk T, so as to disconnect the
gear wheel U from its shaft Q, then the shaft N is turned with the fingers at the
knob to raise the first blind portion Y alone, until the required width of
the slit is attained, and afterwards the claw wheel S is again put into gear with
the loose disk T, so as to couple the gear wheel U with the shaft Q. In this case,
however, the spring in the barrel C attains a greater tension than that in the other
barrel G. On releasing the blind the barrel C would for this reason not stop yet,
when the other barrel & has already unwound the second blind portion K from its
drum L and stretched it out, but the drum L would continue to revolve and again
wind on the second blind portion K and this time in the opposite sense. Then the
sensitive plate would be more or less again exposed to the light which of course is
not intended. I therefore provide for a ratchet wheel G¹ fixed to the spring
barrel G and a pawl G2 gearing thereto and pressed by the spring G³, so as to
check the barrel G, after it has stretched out the second blind portion K. I also
employ a key G for moving the pawl G2 out of gear with the ratchet wheel G', so
as to release the spring barrel G for the purpose of setting the blind shutter.
Outside on the frame A a fork J turning on the bolt J is placed, which can be
brought into either of two positions shown in Figs. 6 and 7 and there secured by
the screw J. In the one position represented by Fig. 7 the one hook-shaped
arm J of the fork engages with the outer claws S₁ of the claw wheel S, while in
the other position of the fork indicated by Fig. 6 the other bent arm Js engages
with the inner claws S¹ of the claw wheel. The fork J is made in two parts J
and J2 linked together at J¹ in the manner, that the top part J engaging with the
claw wheel S can be moved off from the frame A and thereby either release the
claw wheel S or shift it out of engagement with the loose disk T. Between'
the fork J and the frame A a pocket J is placed, which is capable of being
inflated or blown up, so as to move the fork I off from the frame A. The pocket J³
is put in communication through a hose J' with a common hand ball, which
latter is pressed to blow up the pocket J. A spring J' is employed to press the
top part J of the fork back and against the frame A on releasing the hand ball,
when the pocket J8 is no longer blown up.
The blind shutter is put together in the manner, that, when the spiral springs in
the two barrels C G are not stretched, the first blind portion Y is quite wound
upon its barrel C and the second blind portion K also quite wound upon its
drum L. Then the width of the slit between the edges IX of the two blind
portions Y K is the greatest and like the height of the sensitive plate. The
apparatus may, however, be so put together, that the width of the slit is smaller.
The knob Z is now turned to wind the strips W₁ W' on the barrel C around the
first blind portion Y and to unwind the second blind portion K from its drum L
and stretch it out, whereupon the blind shutter is ready for service.
When setting
the blind shutter, i.e. raising both blind portions Y K, the barrels C G are revolved
and thereby their spiral springs stretched, so that the latter are enabled to pull
both blind portions down at once, when the blind is released. The knob Z may be
still further turned to increase the tension of the barrel springs and thereby to
accelerate the downward motion of the blind portions. When the apparatus is not
set, the barrel springs have the same tension.
For instantaneous exposures the blind shutter is worked in the following
manner: The pawl G' checking the spring barrel G is moved out of gear with the
ratchet wheel G¹ by pressing the key G'inwards, then the slit between the two
.

page_text: blind portions Y K is made the required width, whereupon the gear wheel U is
coupled with its shaft Q by putting the claw wheel S into gear with the loose
disk T. The fork J is brought into the one position shown in Fig. 7, in which its
hook-shaped arm J₁ engages with the outer claws S₁ of the claw wheel S. Now
either of the two knobs O and R is turned to raise both blind portions Y K, so as
to stretch out the first blind portion Y. The key G' is then withdrawn, to release
the pawl G. At the proper moment the hand ball is pressed to inflate the
pocket J, which in its turn moves the fork J off and thereby releases the claw
wheel S, when both blind portions Y K will drop.
For time exposures the fork J is brought into the other position shown in Fig. 6,
in which its bent arm J engages with the inner claws $¹ of the claw wheel S.
Then the two blind portions Y K are raised, until the first one Y is quite stretched
out. At the proper moment the hand ball is pressed to blow up the pocket J³,
which in its turn moves the fork J off and thereby shifts the claw wheel S out of
engagement with the loose disk T. Then the shaft N is released and the first
blind portion Y alone drops, so that the sensitive plate is exposed. The pocket J³
being still blown up and the fork J engaging with the claw wheel S, the shaft Q
remains idle, while the claw wheel S has been snatched by the catch R¹.
When
the exposure is finished, the hand ball is released, whereupon the fork J is pressed
back against the frame A and the claw wheel S is released, when the second blind
portion K drops.
The lengths of the blind portions Y K are so determined, that each of them is
capable of shutting the sensitive plate. The strips W1 W¹ and the cords H H on
the other hand are made so long as to allow of the greatest width of the slit.
When it is desired, the blind shutter described above may be simplified by
omitting either the gear wheels P and M or those P¹ and M₁, so as to make the
slit between the two blind portions Y K constant or variable, as the case may be.
Then the one gear wheel P or P¹ left is fastened on the shaft Q, while the movable
sleeve Q and the shaft Q with the eccentric pin Q and the crank Q8 are left out.
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 a photographic blind shutter the combination with the first blind portion Y
stiffened at the edge by the bar X, of the spring barrel C mounted on the shaft B
and arranged to wind on said blind portion when released, the strips W W₁
attached to said bar X, and the fast drums W W mounted on the shaft N and
arranged to wind on said strips and thereby stretch out said blind portion when
setting the apparatus, for the purpose of exposing the sensitive plate by releasing
the shaft N, substantially as shown and described.
1
2. In a photographic blind shutter the combination with the second blind
portion K stiffened at the edge by the bar I, of the loose drum L mounted on the
shaft N and arranged to wind on said blind portion when setting the apparatus,
the cords H H or their equivalents attached to said bar I, and the spring barrel G
mounted on the shaft F and arranged to wind on said cords or equivalents and
thereby stretch out said blind portion, for the purpose of finishing the exposure of
the sensitive plate by releasing the drum L, substantially as shown and described.
3. In a photographic blind shutter the combination with the two shafts B and F
carrying the loose spring barrels C and G respectively and connected thereto by
the enclosed springs, of the equal gear wheels D and E working together, the
ratchet wheel Z' mounted on the one shaft B and checking its revolution in one
direction, the spring-pressed pawl Z or its equivalent engaging with said ratchet
wheel, and the knob Z mounted on the shaft B, for the purpose of giving the
springs inside the spring barrels the same tension, substantially as set forth.
4. In a photographic blind shutter the combination with the shaft N carrying
the fast drums W W for winding on the strips W1 W₁ attached to the first blind
portion Y, of the loose drum L mounted on the shaft N and arranged for winding

page_text: on the second blind portion K when setting the apparatus, the shaft Q arranged
for working with the shaft N by means of the equal gear wheels U V, and the two
gear wheels M P or M' P₁ baving equal or different diameters and working
together, the one M or M¹ of which is fixed to the drum L and the other P or Pi
of which is fastened on the shaft Q, for the purpose of causing the two blind
portions Y K to run off together by releasing the shaft Q, while the width of the
slit between them remains either constant or is made to increase or decrease
respectively during the instantaneous exposure, substantially as shown and
described.
5. In a photographic blind shutter the combination with the spring barrel G winding
on the cords H H or their equivalents and thereby stretching out the second blind
portion K, of the ratchet wheel G₁ and the spring-pressed pawl G³, for the purpose
of checking the spring barrel G, after it has stretched out the second blind
portion K, substantially as set forth.
6. In a photographic blind shutter the arrangement, use and application of the
key G for the purpose of disengaging the spring-pressed pawl G2 from the ratchet
wheel G¹ when setting the apparatus, substantially as set forth.
7. In a photographic blind shutter the combination with the shaft Q, of the loose
disk T mounted thereon and having several holes and working with the shaft N by
means of the gear wheels U V, and the movable claw wheel S or its equivalent
mounted on the shaft Q and prevented from turning and having a pin S² engaging
in any hole of the disk T, for the purpose of either causing both shafts NQ to run
together under the action of the spring barrels C G by releasing the claw wheel S
or its equivalent, while it is engaged with the disk T, or causing first the shaft N
to run alone by disengaging the claw wheel S or its equivalent from the disk T and
afterwards the shaft Q to run alone by releasing the claw wheel S or its equivalent,
substantially as set forth.
8. In a photographic blind shutter the combination with the movable claw
wheel S or its equivalent mounted on the shaft Q, of the spiral spring R2 pressing
the claw wheel or its equivalent against the loose disk T, and the spring-pressed
catch R', for the purpose of holding the claw wheel S or its equivalent disengaged
from the loose disk T, while the latter or the former is released, substantially as set
forth.
9. In a photographic blind shutter the combination with the shaft Q, of the
movable claw wheel S mounted thereon and having claws S₁ S' on both sides, the
turnable fork arranged to be placed in two different positions and made in two
parts J and J2 linked together, the hook-shaped arm J of which engages in the
one position of the fork with the outer claws S¹ and the bent arni J³ of which
engages in the other position of the fork with the inner claws S' of the wheel S,
the inflatable pocket Js for moving the fork part J sidewards, and the spring J' for
pressing the same back, for the purpose of releasing the claw wheel S, when the
fork is in the one position, and of first shifting the claw wheel S and afterwards
releasing it, when the fork is in the other position, substantially as set forth.
10. In a photographic blind shutter the combination with the shaft N, of the loose
drum L mounted thereon and having the two gear wheels M and M², the shaft Q,
the two loose gear wheels P and P mounted thereon and gearing into the gear
wheels M M' and having claws P2 P3 respectively, and the sleeve Q¹ movable
on the shaft while prevented from turning and having at the ends the claws Q³
and Q capable of engaging with those P3 P3 of the wheels P P₁, for the purpose
of imparting the motion of the shaft Q to the loose drum L either through the
gear wheels P M or through the other wheels P' M', substantially as shown and
described.
11
21
ha 1905
LODEWYK JAN RUTGER HOLST.