Improvements in Photographic Camera Shutters.
Year: 1889

page_text: Date of Application, 29th Jan., 1889
Complete Specification Left, 29th Oct., 1889-Accepted, 21st Dec., 1889
PROVISIONAL SPECIFICATION.
Improvements in Photographic Camera Shutters.
I, WILLIAM JAMES LANCASTER trading as J. Lancaster and Son of Colmore Row
in the City of Birmingham Manufacturing Optician, do hereby declare the nature of
this invention to be as follows :-
This invention relates to photographic camera shutters, or apparatus for obtaining
instantaneous or protracted exposure within certain limits, whereby light is allowed to
pass momentarily or otherwise as aforesaid, through the lens or exposure aperture,
at the will of the operator-Thus, the shutter may be made to act instantaneous, or
may be made to acquire varying speeds, according to the length of exposure
required.
The apparatus consists 1st of a double shutter arrangement, which for instan-
taneous exposure, acts in unison, but for protracted or varying exposure, they
act independently of each other-2ndly in shutter holding means, 3rdly in shutter
releasing means, 4thly in suspending and operating the shutters, 5thly in clock or
running down mechanism, which operates a short arm, and removes the holding catch
of the secondary shutter, after a period of time has elapsed since the raising of
the primary shutter-6thly in time stop mechanism and other accessory parts in
connection with the apparatus.
In carrying out my invention, I take a rectangular box like frame, with an
exposure aperture made through it; and sliding and working within guides contained
within the said frame, I arrange two shutters, viz. :-a primary shutter, and a
secondary shutter, which alternately come in front of the exposure aperture.
The primary shutter works in juxta position to the inside back of the front of the
enclosing casing, and with its upper end connected to the outer end of a flexible cord;
whose inner end is connected to a hollow or box pulley, wherein a coiled spring.is
enclosed-This spring is the motive power for raising the shutter from before the
aperture on exposure.
The primary shutter is held in position by a spring catch, working upon, and
through one side of the framing, in a manner that the bolt part of the said catch takes
within a like notch or cut away part in the side of the shutter; so that on the shutter
being lowered or brought in front of the aperture, the catch is moved away by an
incline, and then snaps into the notch.
The spring catch of the primary shutter is cranked at its lower end; and between
it, and the end of a releaser conducting tube, a small flexible bellows is enclosed; so
that by pressing a pneumatic releaser in the form of a flexible tube and ball, the
bellows is expanded, and the catch taken out of action.
The secondary shutter works upon the back, or near the back of the primary one,
and is held in position at two points, viz. on the side, and at the top, whilst it is
taken into its aperture covering position by a flat spring acting upon a stud; and
further, it is taken into its raised position, by the downward movement of the
primary shutter, whose upper end is connected to that of the secondary one by a
flexible cord passing over a pulley mounted at the upper end of the enclosing
casing.
The side fastening is effected by a tumbler catch, in the form of a bell crank lever,
with one arm directed vertically, and the other horizontally; and upon the latter, the
time arm which is on the principal axis of the time mechanism, comes, on the said
mechanism having run down.
The upright or vertical arm carries a knife edged catch or pivot, which engages
with a side notch in the said shutter.
The secondary holding point of this said shutter consists of a spring catch whose

page_text: nose and inclined plane protrudes through the outer casing-This catch forms both a
supplementary holder for the secondary shutter, and a buffer stop to the primary
shutter.
The time mechanism, which consists of a barrel with a volute spring enclosed
within it, a ratchet and pawl arrangement, a large toothed wheel gearing with a
pinion on another axis, and which pinion axis carries a large toothed wheel, which
gears with a second pinion on an axis which carries a third toothed wheel, which
meshes with the teeth of a third pinion, and whose axis carries a fourth toothed wheel,
with the teeth of which, a knife edged stop engages, consisting of a fork like arm
pressed home by a spring, is arranged as aforesaid.
The axis which carries the drum, ratchet wheel, and primary toothed wheel as first
named, is the same axis as carries the time arm. Thus, the moving of a turn carried
on the said time arm axis, through a portion of a circle, winds the spring up to an
extent equivalent to a unit of time, which when released, is allowed to run down only
at a certain rate by the reduction gear or train of wheels as aforesaid.
The turn for giving varying speeds to the shutters, or rather to the secondary
shutter, is provided with a pointer, which traverses in front of a graduated and set out
dial, indicating one, two, three or more seconds, and portions of them.
The action of the apparatus or shutter for instantaneous exposure is as follows
The exposure aperture is covered by the pulling down of the primary shutter,
which is held by its catch, while the secondary shutter is held by the top catch, which
is the buffer stop to the primary one.
When the parts are in the positions as indicated, that is, the primary shatter down,
and the secondary one up, the ball end of the pneumatic releaser is pressed, when the
bellows at its other end is distended, and the spring catch released from the primary
shutter, which now being free, to instantly drawn upwards, by the spring enclosed
within the pulley, to which the flexible cord of the shutter is attached.
The rising and striking of the said shutter against the buffer stop catch, liberates
the said shutter, which is pressed down in front of the aperture by a spring.
For a greater exposure, the time required is fixed by placing the pointer in front of
one of the markings on the dial, which determines the exposure required; this is
done after the primary shutter has been brought before the aperture-Thus the
primary shutter has been pulled down, and there held by its catch, and the secondary
shutter pulled upwards, and held by the buffer stop catch; this done, the time for
exposure is determined by moving the turn and pointer to the required position, when
the secondary shutter holding stop carried by the bell cranked arm passes into the
notch on side of said shutter, and holds it there.
The affixing of the shutter by the lower and side catch, is done by a spring, acting
upon it, when the time arm on the time axis mechanism is removed, by the rotation
of the turn and finger.
The pressing of the pneumatic releaser distends the bellows, removes the catch
from the primary shutter, which is raised by the coiled spring from in front of the
exposure aperture, and releases the buffer stop catch from the secondary shutter, and
also takes the knife edged stop from the teeth of the top wheels of the train of wheels,
which now being free, run down at a determinate rate, and bring the time arm upon
the top side of the horizontal arm of the bell crank catch, liberating the secondary
shutter, which is now pressed down by the spring, and comes in front of, and closes
up light tight, the exposure aperture.
It will be thus observed, that the secondary plate follows the movement of the first
one, after a certain definite period of time, and that the time stop is released, by the
primary shutter coming against it.
Dated this Twenty fourth day of January 1889.

page_text: COMPLETE SPECIFICATION.
Improvements in Photographic Camera Shutters.
I WILLIAM JAMES LANCASTER trading as J. Lancaster & Son of Colmore Row in
the City of Birmingham Manufacturing Optician 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 camera shutters, or apparatus for obtaining
instantaneous or protracted exposure within certain limits-whereby light is allowed
to pass momentarily or otherwise as aforesaid through the lens or exposure aperture,
at the will of the operator-Thus, the shutter may be made to act instantaneous, or
may be made to acquire varying speeds, according to the length of exposure
required.
The apparatus consists 1st of a double shutter arrangement, which for instantaneous
exposure, acts in unison but for protracted or varying exposure they act independently
of each otber-2ndly in shutter holding means, 3rdly in shutter releasing means
4thly in suspending and operating the shutters, 5thly in clock or running down
mechanism which operates a short arm, and removes the holding catch of the
secondary shutter, after a period of time has elapsed, since the raising of the primary
shutter-6thly in time stop mechanism and other accessory parts in connection with
the apparatus.
In carrying out my invention, 1 take a rectangular box like frame, with an
exposure aperture made through it; and sliding and working within guides contained
within the said frame, I arrange two shutters viz. :-a primary shutter, and a
secondary shutter, which alternately come in front of the exposure aperture.
The primary shutter works in juxta position to the inside back, of the front of the
inclosing casing, and with its upper end connected to the outer end of a flexible cord,
whose inner end is connected to a hollow, or box pulley, wherein a coiled spring is
enclosed-This spring is the motive power for raising the shutter from before the
aperture on exposure.
The primary shutter is held in position by a spring catch, working upon, and
through one side of the framing, in a manner that the bolt part of the said catch takes
within a like shaped notch or cut away part in the side of the shutter; so that on the
shutter being lowered or brought in front of the aperture, the catch is moved away by
an incline, and then snaps into the notch.
The spring catch arm of the primary shutter is cranked at its lower end; and
between it, and the end of a releaser conducting tube, a small flexible bellows is
enclosed so that by pressing a pneumatic releaser in the form of a flexible tube and
ball, the bellows is expanded, and the catch taken out of action.
The secondary shutter works upon the back, or near the back of the primary one,
and is held in position at two points, viz. -on the side, and at the top, whilst it is
taken into its aperture covering position by a flat spring acting upon a stud; and
further, it is taken into its raised position by the downward movement of the primary
shutter, whose upper end is connected to that of the secondary one by a flexible cord
passing over a pulley mounted at the upper end of the enclosing casing.
The side fastening is effected by a tumbler catch, in the form of a bell crank lever,
with one arm directed vertically, and the other horizontally; and upon the latter, the
time arm which is on the principal axis of the time mechanism, comes, on the said
mechanism having run down.
The upright or vertical arm carries a knife edged catch or pivot, which engages
with a side notch in the said shutter.
The secondry holding point of this said shutter consists of a spring catch, whose
nose and inclined plane protrudes through the outer casing-This catch forms both a
supplementary holder for the secondary shutter, and a buffer stop to the primary
shutter.
The time mechanism which consists of a barrel, with a volute spring enclosed

page_text: within it, a ratchet and pawl arrangement, a large toothed wheel gearing with a
pinion, on another axis, and which pinion axis carries a large toothed wheel which
gears with a second pinion, on an axis which carried a third toothed wheel which
meshes with the teeth of a third pinion, and whose axis carries a fourth toothed wheel,
with the teeth of which a knife edged stop engages, consisting of a fork like arm
pressed home by a spring, is arranged as aforesaid.
The axis which carries the drum, ratchet wheel and primary toothed wheel, as first
named, is the same axis as carries the time arm-Thus, the moving of a turn carried
on the said time arm axis, through a portion of a circle, winds the spring up to an
extent equivalent to an unit of time, which when released, is allowed to run down
only at a certain rate by the reduction gear or train of wheels as aforesaid.
The turn for giving varying speeds to the shutters, or rather to the secondary
shutter, is provided with a pointer, which traverses in front of a graduated and set
out dial indicating one, two, three or more seconds, and portions of them.
The action of the apparatus or shutter for instantaneous exposure is as follows-
The exposure aperture is covered by the pulling down of the primary shutter, which
is held by its catch, while the secondary shutter is held by the top catch, which is the
buffer stop to the primary one.
When the parts are in the positions as indicated, that is, the primary shutter down,
and the secondary one up, the ball end of the pneumatic releaser is pressed, when the
bellows at its other end is distended, and the spring catch released from the primary
shutter, which now being free, is instantly drawn upwards, by the spring enclosed
within the pulley, to which the flexible cord of the shutter is attached.
The rising and striking of the said primary shutter against the buffer stop catch,
liberates the said secondary shutter which is pressed down in front of the aperture by
a spring.
For a greater exposure, the time required is fixed by placing the pointer in front of
one of the markings on the dial, which determines the exposure required; this is done
after the primary shutter has been brought before the aperture Thus, the primary
shutter has been pulled down, and there held by its catch, and the secondary shutter
pulled upwards and held by the buffer stop catch; this done, the time for exposure is
determined by moving the turn and pointer to the required position, when the
secondary shutter holding stop carried by the bell cranked arm passes into the notch
on side of said shutter, and holds it there.
The affixing of the shutter by the lower and side catch is done by a spring, acting
upon it, when the time arm on the time axis mechanism is removed, by the rotation
of the turn and finger.
The pressing of the pneumatic releaser distends the bellows, removes the catch
from the primary shutter, which is raised by the coiled spring from in front of the
exposure aperture, and releases the buffer stop catch from the secondary shutter, and
also takes the teeth of the top wheel of the train of wheels, which now being free run
down at a determinate rate, and brings the time arm upon the top side of the
horizontal arm of the bell crank catch, liberating the secondary shutter, which is now
pressed down by the spring, and comes in front of, and closes up light tight the
exposure aperture.
It will be thus observed that the secondary plate follows the movement of the first
one, after a certain definite period of time, and that the time stop is released by the
primary shutter coming against it.
Figure 1 of the accompanying drawings, represents in front elevation, a
"Chronolux" time shutter constructed, arranged, and operated according to my
invention, with the same shown ready for exposure.
Figure 2 represents a back elevation (partly in vertical section) of the said shutter,
with the back plate of the enclosing casing, removed-This said view, represents both
the primary and secondary shutters, the former covering-up the light aperture, and
the latter held in an elevated position, which is only released, by the fully ascending 5
movement of primary shutter-The view also represents the pneumatic releaser, and
also the holding catch, and its arm, and with other accessory parts.

page_text: Figure 3 represents a like view as figure 2, but with the parts in the positions
which they assume on and after releasing, ci. -the distension of the pneumatic
bellows releaser, by pressure exerted upon the ball end in communication with it,
directs outwardly the spring arin of the holding catch, and allows the primary shutter,
which is under tension or pull of a wound up spring, to ascend, and at the end of its
course, to strike against, and release a catch which allows the secondary shutter to
descend, as is shown.
Figure 4 represents a transverse section, on the dotted lines A B, figure 3, thus
exhibiting the secondary, and primary shutters, and also some of the accessory parts.
Figure 5 shows the normal positions of the parts of the appliance, viz.:-the
primary shutter elevated, and the secondary shutter, closing the light aperture.
Figure 6 represents a transverse section of the appliance, upon the dotted lines CD,
figure 5.
Figure 7 represents a transverse vertical section on the dotted lines E F, figure 5.
Figure 8 shows the shutters, in like positions as figures 1 and 2, but with the
time mechanism set and arranged, to give a protracted exposure, after the primary
shutter, has ascended, and thereby leaving exposed for a period of time the light
aperture.
Figure 9 represents a like view as figure 8 but with the primary shutter raised,
and the time mechanism, for giving the necessary protracted exposure partially run
down.
The said figures 1, 2, 3, 4, 5, 6 and 7 represent the parts of the appliance in the
positions which they assume, for instantaneous exposure, whilst the succeeding
figures 8 and 9 represent the shutters, and the parts in the positions which they
normally assume, for protracted or time exposure.
The same letters of reference, indicate corresponding parts in the several figures of
the drawings.
a is a shallow rectangular shaped box frame and a² a light, or exposure aperture,
made through it, b, is a primary sliding shutter, and c is a secondary shutter and
which shutters respectively work within vertical guides d', of upright stiles d,
disposed within the said frame on the two opposite sides of the shutters.
The primary shutter b, works in close proximity to the inside back, of the front of
the enclosing casing, and with its upper end 62 connected to the outer end of a
flexible corde, whose inner end e³, is connected to a hollow or box pulley f, wherein
is coiled spring g, is enclosed and which spring, when wound up, or the coils brought
in closer proximity, created by the pulling down of the primary shutter, is the
motive-power for operating, or raising the said shutter. The said pulley turns upon
an axis, to which the inner end of the coiled spring, is attached, whilst the outer
end of the said spring, is connected to the inside of the pulley, so that by the pulling
down of the primary shutter b, by its thumb piece 68, the spring is wound up, and by
it, the shutter is again raised, when released. 2 is a primary shutter catch, carried
by a releaser spring arın h, with a limiting stop ³, and a cranked free end / coming
upon a pneumatic bellows releaser i at the outer end of a tube *, connected with a
flexible tubing, whose outer end, has an inflated rubber ball, which on being
compressed, creates pressure of the air within it, and opens out, or distends the
bellows, which through its intervention, the releaser spring arm h, is bent outwards,
and removes the catch from the notch of the shutter b, with which it engages:
so that on the shutter being lowered, and brought in front of the aperture, a², the
catch is moved away, by an incline 6, and then snaps into the notch 6, as aforesaid.
The secondary shutter c, works at the back of the primary one b, and is held at two
points, viz. on the side at c³, and at the top at c³, whilst it is taken into its aperture
covering position, by the arm 3, of the flat spring j, acting within an eye, or upon a
stud c; and further, the said secondary shutter, is taken into its raised position by an
attached and flexible cord k, connected to the primary shutter, and passing over a
pulley, suspended from a bracket, hanging from the top inside edge of the
enclosing casing.
Thus, the ends of the cord, are attached respectively to the shutters, whilst the

page_text: middle part, passes over a pulley, so that the pulling down of the primary shutter, to
the position as represented in figures 1, 2, and 8, raises the secondary shutter, through
the intervention of the said cord.
The holding of the secondary shutter, by the side, is performed, by a tumbler
with arms, pivot l, and catch 1, which latter engages under the shoulder c³, of
the said secondary shutter c.
The tumbler is limited in its movement, by upper and lower stops, and is taken
into its acting position by a carried spring 18.
Working at the back of the tumbler, is a time arm m, made tight on the principal
axis m³, of time mechanism, consisting of a series of wheels and pinions, as hereinafter
described.
The upper holding device of the said secondary shutter, consists of a combined
spring catch and buffer n, n³, the former engages with the piercing c³, while the
latter n², forms an anti-concussion means, for the primary shutter, and also an
expedient for releasing the catch n, from the piercing of the secondary shutter, so as
to allow the said secondary shutter to be pressed downwards, either on, or after, the
fully rising of the primary shutter.
The time mechanism, consists of a barrel o, with volute spring o², within it, and
which spring's outer end, is connected to a stud o³, and its inner end, to the principal
axis m; and made fast, upon which said axis, is a ratchet wheel m³, and a finger p,
traversing in front of a dial p³, and within the middle of which, is a turn p³, which is
the outer end of the said axis.
The ratchet wheel m³, has a pawl m³, and retaining spring m³, whilst also made fast
upon the aforesaid principal axis, is a toothed wheel 9, gearing with a pinion g³,
whose axis q, carries a second toothed wheel 9, which in turn gears with a second
pinion 9, whose axis 7º, carries a small toothed wheel q', which engages or meshes
with a third pinion 8, having upon its axis q³, a fourth toothed wheel q, with the
teeth of which, a knife edged stop ², of a jointed drop-arm r, engages.
The said drop arm r, is raised, and its knife edged catch, removed from the teeth
of the wheel 10, by the incline 6º, of the primary shutter b, of impinging against it,
on the fulfilment of its upward movement.
Thus, the axis, which carries the drum, ratchet wheel, and primary toothed wheel, is
the same that carries the time-arm; so that the moving of a turn, carried on the said
time-arm axis, through a segment, or portion of a circle, (which is equivalent to an
unit of time) is when liberated by the drop-arm, allowed to run down at a certain
chronometric speed.
The drop arm is pressed down by the spring ³.
The primary shutter besides being buffered or cushioned by the incline_n³, its
impact is broken on reaching its upward traverse, by the lower free end n³, of a
spring n¹, to which the bolt catch n, and incline n² are carried at its inside 4
upper end.
The impingement takes place between the thumb piece ³, and the said free end,
and further, the secondary shutter, has impressing upon it, a tongue spring 8, to
cushion it, or retard its motion at the termination of its down traverse.
The speeding of the primary shutter, is performed by moving the axis f1 and 4
winding up the spring g, which is held by a cottar f³, passed through the axis, and
coming against a stud
OPERATION FOR INSTANTANEOUS EXPOSURE.
The exposure or light aperture a³, being closed by the primary shutter b, and the
parts in the respective positions which they assume in figures 1 and 2, with the
secondary shutter c, held by a single catch bolt n, the ball of the pneumatic releaser i,
is pressed, when the air within it transmite

page_text: bolt catch n, is pressed upwards, out of the catch piercing c³, of the secondary
shutter, which now being free, is pressed downwards, by the spring arm 7, of the
spring j, into the position covering the exposure or light aperture, as represented in
figure 5.
FOR A PROTRACTED EXPOSURE.
Place the shutters in the position again as represented at figures 1 and 2, then
place the pointer or finger p, by means of the turn p³, in front of one of the
chronometric markings on the dial p³, when the act of placing the said pointer as
aforesaid, also sets the time arm back, to a position as represented in figure 8, and
also relieves pressure from the arm ; of the tumbler 4, which through the spring 1®,
has its arm, brought forward, and the catch 1, carried by it, brought under the
shoulder, of the secondary shutter c, thereby holding the said shutter at a second
point, viz. on the side.
The setting back of the pointer, winds up the going mechanism, so that on pressing
the pneumatic releaser, the bellows, is distended, and removes the catch from the
primary shutter, which being then free, is raised by the coiled spring (from in front
of the exposure aperture) and on striking the buffer stop catch n³, releases the catch
bolt n, from the secondary shutter, and by the incline 6, coming against the drop-
arm r, raises it, and takes the knife edged stop r³, from the teeth of the top wheel.
which now being free, by such removal, allows the train of wheels to run down at a
determinate rate, and on the completion, or just before, the completion of the said
running down, the time arm m, is brought upon the top of the arm 13, of the
tumbler, and thereby turning its fore part rearward, and so taking the stop catch
clear of the shoulder c³, of the secondary shutter c, which now being free is pressed.
downwards by the arm of the spring j, after a certain chronometric unit of time has
elapsed since the raising of the primary shutter, as represented in figures 3 and 5, of
which figure 3 shows the secondary shutter descending.
The shutters may be made to work in a horizontal plane, and to lap or move one
over the other, in reverse directions. In this case, I prefer that the shutters
themselves, should be pierced with exposure apertures, alike unto the aforesaid
apertures, so that the sliding of the plates, one over the other, cuts off the respective
piercings and aperture.
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 :-
First Arranging two shutter plates, to work in reverse directions, for instan-
taneous and protracted exposure, substantially as described and set forth.
Secondly-Coupling together double shutter plates, of the construction as herein
described, by a flexible cord, or chain, acting substantially, as and for the purpose, as
described and set forth.
Thirdly-Holding and cushioning the primary shutter plates, of instantaneous
camera shutters, by means of a catch n³, carried by an arm n, for holding and
releasing, and for cushioning by an incline n³, and spring n², n³, substantially as set
forth.
Fourthly-Operating a camera shutter, by means of a coiled spring enclosed
within a pulley, whose axis admits of being turned for speeding, and the connection
between which pulley and shutter, is made by a flexible cord, substantially as
described and set forth.
Fifthly-Releasing the second shutter plate of a double shutter camera from its
holding catch, by means of the impact or motion of a first moving or primary shutter
plate, substantially as described and set forth.
Sixthly-Holding a secondary shutter plate, of a double shutter arrangement, as
described, at two points, for the purpose of allowing the said secondary shutter plate,
to have a period of rest, until the primary shutter has nearly completed its movement,
substantially as described and set forth.

page_text: Seventhly-Holding the secondary shutter for a period of rest, during the running
down of a train of wheels, by means of a catch or stop, carried by a tumbler, sub-
stantially as described and set forth.
Eighthly The means herein described, and set forth, for the taking of a tumbler
stop, clear of the shutter plate, and also the means for taking the said stop into
position for the holding of the said stop into position, for the holding of the said
shutter plate, substantially as set forth.
Ninthly The combination with time mechanism and double shutter plates, of a
photographic camera shutter, of a time arm m, for the taking out of position and
placing into position of a shutter stop, substantially as described and set forth.
Tenthly The combination with the releasing and timing means of a camera
shutter, of dial, pointer, turn, time arm, and tumbler with stop, substantially as
described and set forth.
Eleventhly-Releasing the timing or running down mechanism, by means of an
arm, operated by a shutter, substantially as described and set forth.
Twelfthly: The construction, combination, and arrangement of the parts of
double-plate camera shutters for instantaneous exposure, as herein described and set
forth.
Thirteenthly:-The construction, combination, and arrangement of parts, of double
plate camera shutters, for protracted exposure, substantially as described and set forth.
Fourteenthly-A photographic camera shutter, of which the parts are constructed,
arranged, and operate and co-operate, in manner, and in the ways, and for the
purpose, substantially as described and set forth.
Dated this 90th
Otahan 1000
WILLIAM JAMES LANCASTER.
By Henry Skerrett,
Agent for Applicant.