Improvements in Photographic Camera Shutters.
Year: 1889

page_text: Date of Application, 14th Nov., 1889
Complete Specification Left, 14th Aug., 1890-Accented, 4th Oct,
1890
PROVISIONAL SPECIFICATION.
Improvements in Photographic Camera Shutters.
I, WILLIAM JAMES LANCASTER 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 camera shutters, or means, for obtaining instantaneous or
extended exposure, whereby light is allowed to pass momentarily, or otherwise,
through the lens or exposure aperture, at the will of the operator; and which said
invention, designated by me the Chronolux" time shutter, is an improvement upon
Application for Letters Patent made by me on the 29th day of January 1889, and
numbered 1543.
The apparatus consists
1st. Of two circular pierced shutter plates, sliding in reverse directions to and fro
upon each other, in manner, that the pierced and unpierced parts respectively overlap
each other, and thereby either form an opening, or close one.
2ndly. In means for working the shutter plates.
3rdly. In a pneumatic operator and reloaser.
4thly. In the combination of the time mechanism, described in my cited patent,
with the operating means, and circular pierced shutter plates, as aforesaid.
In carrying out one form of my present invention, I employ a rectangular box
shaped frame, with a circular exposure aperture, through its middle; and working
within the inside of the said frame, 1 arrange two sliding and circular pierced
shutter plates, of which the piercings, are of the same diameter, as the exposure
aperture, and are so arranged, that the unpierced part of the one plate, comes in front
of the pierced part of the other plate respectively; so that the upper boundary edge
of the piercing of one plate, is approximate to the lower part of the boundary edge of
the other plate, and on the plates moving in opposite directions, the piercings overlap
each other, to an extent of the throw of the plates, until the piercings become
coincident with each other, and with the exposure aperture.
The overlapping of the piercings, by the moving of the plates in opposite directions,
forms a constant recedance to and from a common centre, which is the exact middle
of the exposure aperture, in the carrying frame.
The shutter plates are worked by studs upon them, taking into slots at the outer
ends of a centrally pivoted rocking lever, which when turned from an oblique to a
horizontal position, causes the shutter plates to be moved in opposite directions, and
an aperture made thereby, consequent upon the overlapping of the piercings.
The studs are directed in parallel slots, to ensure the direct sliding of the plates.
To limit the movement of a rocking lever, 1 arrange swinging and fixed stops,
which when placed in varying positions, determine the throw of the plates, and size of
opening required; and further, the lever is brought back to its normal and closing
position, by a spring.
I work the operating lever, by means of a pneumatic pusher and releaser, consisting
of a bag or bellows, carried by a bracket, fitted at the end of a flexible tube, with a
pressure ball at its end; so that by pressing the said ball, the bellows are distended,
the lever upon which it impinges, turned upon its centre, and the shutter plates
opened.
On relaxing pressure upon the ball, the pneumatic appliance resumes its normal
condition, with the rocking lever pulled into its closed position, by the spring, which
was distended by the pressure exerted upon the lever in opening.

page_text: I wish it to be observed, that the plates in making the complete throw for
instantaneous exposure, first open, and then close, by the continuous traversing of the
piercings.
In another form of my invention, I arrange in a time shutter, that the lever as
aforesaid, shall be retained after the fully opening of the plates, and then subsequently
relieved or released, after a chronometric unit of time, which then automatically close.
In connection with the said shutters, I prefer to employ the "Chronolux" time
mechanism, as described and represented in the aforesaid cited patent; so that for
extended or time exposure, the shutter plates are opened, then after a period of time,
by the running down of the mechanism, they are automatically closed.
In further carrying out my invention, 1 take a shutter, as described in the aforesaid
patent, and pierce the primary and secondary shutter, with overlapping piercings,
which come coincident with the exposure aperture, when the said piercings come
together, in part, or in whole.
Thus, the exposure aperture being closed. the pneumatic releaser is then pressed,
when the spring which operates the shutters, slides the shutters, and the shutter
apertures, past each other, and when extended or time exposure is required, the said
shutters are retained for a determined period, and then released by the running down
of mechanism, which operates an arm, which on coming in contact with a catch,
liberates it, and allows the shutter plates to close.
Dated this 13th day of November 1889.
WILLIAM JAMES LANCASTER.
By Henry Skerrett,
Agent.
COMPLETE SPECIFICATION.
Improvements in Photographic Camera Shutters.
I, WILLIAM JAMES LANCASTER, 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 camera shatters, or uncans, for obtaining instantaneous or
extended exposure, whereby light is allowed to pass momentarily, or otherwise,
through the lens, or exposure aperture, at the will of the operator; and which said
invention, designated by me the Chronolux" time shutter, is an improvement upon
Letters Patent, granted to me and bearing date the 29th day of January 1889, and
numbered 1543.
My said invention consists in the first part, in the employment of two circular
pierced plates, (virtually constituting the shutter) and which slide in reverse
directions upon each other, in manner, that the pierced and unpierced parts,
respectively become coincident and overlap each other, for exposure and shutting off.
In the 2nd part, to means for working the shutter plates, for either instantaneous
or protracted exposure.
In the 3rd part to a pneumatic operator and releaser.
In the 4th part in the combination of the shutter arrangement, with the time
mechanism described in my said cited Letters Patent.
In carrying out one form of my present invention, 1 employ a shallow rectangular
box shaped frame, having a circular shaped exposure aperture through its middle
part, over which I arrange two sliding and circular pierced shutter plates, of which
The piercings are of the same diameter as the exposure aperture. These plates are so
arranged, that the unpierced part of the one plate, comes in front of the pierced part
of the other plate, when the shutter is closed, and with the piercings of both coincident
when opened. Thus the boundary edge of the piercing of one plate, is approximate
to the lower part of the boundary edge of the other plate, and on the plates moving

page_text: in opposite directions, the piercings overlap each other, to an extent of the throw of
the plates, until the piercings become coincident, and with the exposure aperture.
The overlapping of the piercings, by the moving of the plates in opposite directions,
forms a constant recedence to and from a common centre, which is the exact middle
of the exposure aperture, in the carrying box-like casing.
The shutter plates are worked by studs upon them, taking into slots at the outer ends
of a centrally pivoted rocking beam, which when turned from an oblique to a
horizontal position, causes the shutter plates to move in opposite directions, and the
overlapping of the piercings thereby.
To limit the movement of a rocking lever, swinging and fixed stops are arranged,
in varying positions, according to exposure required.
I work the operating lever by means of a pneumatic pusher or forcer, consisting of
a bag or hollow ball at the end of a flexible tube, so that by pressing the said ball,
the plunger is forced upwards, the beam turned upon its centre, and the shutter plates
made to slide, or be reciprocated.
In a further form of iny invention, in connection with a time shutter, I arrange
that the rocking beam shall be retained after the opening of the shutter, for a
chronometric unit of time, and at the end of such time, the same shall then reverse
itself, and automatically close the shutter.
Thus in connection with the said shutter, with plates working as described, I prefer
to use the "Chronolux" time mechanism, as described, but to this I do not limit
myself, as other time mechanism may be employed with nearly the same effect.
As a further modification of my invention, I take a shutter, alike as described in
the aforesaid patent, and pierce the primary and secondary shutter, with overlapping
piercings, which come coincident with the exposure aperture, when the said piercings
come together.
Figure 1 of the accompanying drawings, represents a back elevation, partly in
vertical section, of a combined instantaneous, and time photographic camera shutter,
constructed, arranged, and operated, according to my invention. It will be observed
that the shutter plates, which are super and substratumly arranged, have centrally
disposed piercings, of like diameters to that of the exposure aperiure, and that the
said plates are made to slide in reverse directions one upon each other, by their con-
nections with the slotted ends of a rocking beam pivoted about its middle, and adapted
to create a transposition, or transmutation, of the piercings, with respect to each other
and the said aperture.
The beam is worked by air pressure, created by the pressing of an inflated rubber
sphere or ball, terminating the end of a tube, and by which means, the shutter is
operated, for instantaneous, or detention exposure.
Figure 2 represents a longitudinal vertical section of the shutier Figure 1, upon the
dotted lines A B. From this view, it is clearly seen, how the super, and substratum
plates, lie upon each other, and how by the sliding of them in opposite directions
from a point common to them both, the pierced, and unpierced parts of them, overlap
each other, for exposure and cutting off.
Figure 3 represents a front elevation, with the parts in the positions which they
respectively assume in Figure 1, but with the covering plate removed, in order to
show the connections of the plates with the ends of the beam, and also the positions
of the piercings, with respect to the exposure aperture, when the shutter is closed.
Figure 4 is a like view as Figure 3, but with the exposure aperture partially opened,
by the overlapping of portions of the pierced parts of the plates, to an extent equal
to the throw that the said plates have acquired, the further movement of the plates,
creating complete exposure, consequent upon the said pierced parts of the plates,
becoming coincident with each other, and the exposure aperture, which on the
plates being still further traversed, the transmutation of their piercings, creates a
gradual diminution of aperture, to complete cutting off, as represented in Figure 5,
where the unpierced parts of the plates, are shown completely overlapping the
exposure aperture.

page_text: It will be observed in the said view Figure 5, that the rocking beam, to the ends of
which, the plates are respectively connected, has changed its direction, by inclining
from left to right, instead of from right to left, as in the pre erding Figures
and 4.
Figure 6 is a back view of the upper portion of Figure 5, while Figure 7 is a part
vertical section of Figure 6, on the dotted lines (; D.
Figure 8 represents a back clevation of the said shutter, arranged for diuturnity
exposure, through the agency of the pressure of the hand applied detentatively upon
the pneumatic sphere, thus allowing greater or less exposuro, according to the time
which the hand exerts pressure.
Figure 9 represents a front and edge view of the substratum pierced plate,
separately, and Figure 10, like views of the super stratum plate.
The same letters of reference indicate corresponding parts in Figures 1 to 10.
a is a shallow rectangular box shaped casing, having about its middle, a circular
shaped exposure aperture 6. wherethrough light to the camera inwardly passes.
Enclosed within the said casing, and sliding in reverse directions, one upon another,
or to and fro one upon another in reverse directions, for varying kinds of exposure,
are sub and superstratum plates c, d, with circular piercings c, d respectively, of a
like area or diameter, as the piercing constituting the exposure aperture b.
The substratum plate is marked c, and the superstratum d, and which plates are
worked, and caused to slide in opposite directions by cars c³, ds of them, carrying
studs c, d, working within upright race slots a³, a³, of the casing a, and taking into
slots e, eat the ends of a rocking beam e, pivoted about a pivot e, as a centre, so
that as the said beam oscillates or rocks in a see-saw manner, the plates are made to
slide in reverse directions one upon another, as already described.
The stud has threaded upon it, the upper end f, of the hollow plunger f, with
open end, closed end 4, and an inlot and outlet hole f, enclosed with an open
topped cylinder or tube 9, connected at its lower end, with a flexible tube h, terminated
by an inflated pear-shaped ball i.
The race slot a³, bas at its upper end, a spring buffer j, which acts both for cushioning
the beam, at the end of its upward stroke, and also for retaining the same, after having
completed its desired movement, with the shutter closed.
OPERATION FOR INSTANTANEOUS EXPOSURE.
Place the beam with its cognate parts, in the positions which they respectively
assume in Figures 1, 2, and 3, then squeeze the ball, which compresses the air
within it, and causes the same to travel up the tube h, to the hollow plunger, when
the same is raised, and by its movement, turns the beam e, upon its fulcrum e, which
said beam, being connected at its ends to the plates caud d, gives a corresponding
movement to them, which are made to slide race-like in reverse directions, one over
the other, so as to first bring the piercing of the one, opposite the piercing of the
other, and the exposure aperture, and then the gradual overlapping of the unpierced
parts respectively of the said plates, over the exposure aperture, till the said aperture
is fully closed, as in Figures 5, 6, and 7, when the beam is cushioned and held in the
positions in the aforesaid last named figures, by the spring buffer j.
Immediately the hollow plunger, arrives at the end of its stroke, the compressed
air within the tube, escapes, and on pressure being relieved from the inflated ball or
forcer, i, the same is allowed to be again inflated, by air passing through the said
hole, down the plunger, through the tube to it.
The length of the exposure is dependent upon the acceleration of the plunger
consequent upon the degree of compression upon the pneumatic forcer.
DLL.
OPERATION FOR DETENTION EXPOSURE.
...
n
4

page_text: pressure by the hand grasping the pneumatic ball or forcer, when the plunger fis
raised, the beam e, turned to a horizontal position as in Figure 8, thus stopped by
coming against the stop k. This partial movement of the beam, slides the plates in
reverse directions, which brings their piercings, and the exposure aperture, coincident,
which remains so as long as pressure is exerted upon the pneumatic ball or forcer,
but instantly pressure is relaxed, then the gravitating weight of the parts causes the
shutter to close, by the reverse movement of the plates.
Thus the operation of exposure is performed by pressure applied, and exposure
dependent upon the time that the said pressure is applied.
Figure 11 represents an enlarged view of a camera time shutter, constructed
according to my said cited former Letters Patent, "Chronolux Time Shutter," and
provided with plates or means of exposure according to my present invention. The
said view represents the parts in the positions which they respectively assume after
exposure and before the shutter is set.
a is a shallow rectangular box shaped casing, and a², a light or exposure aperture,.
made through it. b is a primary sliding shutter, with pierced middle 6¹, and c is a
secondary shutter, with piercing and which shutters respectively work within
vertical guides d', d², of upright stiles d, disposed within the said casing.
The primary shutter b, works in close proximity to the inside back of the front of
the enclosing casing, and with one side of its upper end, provided with a stud b³,
which works within a race a³, of the casing, and takes within a slot e", at one end of
a rocking beam e, turning about a centre e^, and having an upright arm e, for
the movement of the boam, on taking the shutters into their normal and set
positions.
The beam is supported from a forked hanging bracket e.
The other end of the beam is slotted, (marked e¹) wherein a pivoted stud block c³,
carried by the shutter c, slides, on the rocking of the said beam.
The shutter b, has an abutment shoulder 63, and a holding shoulder 64, wherewith
the pin, carried by a bell crank lever 1, engages and holds the shutters in their
"time" position, or with the piercings of plates and casing, coincident.
The lever is jointed at 13, and acts pawl like, as a stop for the plato b.
This
n is a wheel, carrying a pawl and spring n², upon axis n³, surrounded by a volute
spring o, connected at one end to the axis, and at the other end to the casing.
axis is both winding and finger axis, which has been clearly described in the
Chronolux " patent before cited.
EE
is an arm, also upon the said axis, and turns with it, and forms a releaser, for
taking the stop out of position, after the predescribed exposure, has expired.
P, P², PPP, p, p, are wheels and pinions for constituting the necessary time
and reduction gear.
9 is an escapement, jointed at g², with a pallet g³, and arm q, which is pushed
back by the shoulder 63, of the plate b. The plates b, and c, are kept in a state of
tension, or moved in reverse directions, by springs r, ², suitably connected to the
said plates. s is a switch, with a pin s², directed into the casing, and coming opposite
the shoulder, of the plate b, so that on the rising of the said plate, the end s³, of
the switch, is taken from the back of, and above the pneumatic releaser bellows arm t³,
of the bellows t, so as to allow the pin t3, to take an acting position, and it will be
understood, that the said switch is upwardly pushed by the plate, when the switch is in
its position as represented.

page_text: spring arm, which allows the stud or pin 3, to pass inwardly into the casing, and
come under the shoulder or bottom 68, of the plate b, retaining both plates thereby in
an active position.
The switch or bar s, is drawn down for keeping the studs out of position, by a
spring u.
The moving of the one plate, compels the other plate to move with it, but in an
opposite direction, in consequence of the said plates being connected to the ends of
the beam respectively. Thus it will be seen, that as the platos can only act in
unison, the holding or releasing of one plate, holds or releases both of them
simultaneously.
The shutter now being set, and its plates held, turn forward the pointer, through
the milled head on its axis, when the coiled spring o, will be wound up, and the
pawl n², slip over the teeth of its ratchet wheel, and retain the said wound-up spring,
in a state of tension according to the exposure required, or according to the extent
which the pointer has been turned, which takes the arm, forward to a corresponding
position. This done, squeeze the pneumatic releaser ball, attached to the pipe v, when
the air compressed, is transferred to the bellows t, which are distended, and the
holding stud or peg t³, removed, by the spring arm, being carried with the said
bellows; the consequence is, that the pressure exerted by the springs r,, upon the
plates, which are now free, causes the said plates to slide in roverse directions over
each other, and on the piercings b, c, becoming coincident with the piercing a², the
plate b, is caught, and so holds both plates in an exposure position, by the stud 1³, of
the lever l, coming under the shoulder 6, of the plate b, while the shoulder or exten-
sion 63, pushes back the arm q', of the stop 9, and removes the pallet q³, from the teeth of
the wheel p, thereby allowing the time mechanism to run down, to the extent wound up,
and bring the arm t*, under the outstanding arm of the lever 1, which on being turned
upwardly, takes the stud, from under the shoulder 64, when the plates are simulta-
neously released, and the shutter closed, with the parts taken back to the positions
which they normally assume in Figure 11.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
First: An instantaneous or time camera shutter, employing or using in connection
with the ordinary exposure aperture of a camera, or the enclosing casing of a camera
shutter, two circular pierced and reverse sliding plates, arranged that the direct
sliding of the said platos one over the other, and in roverse directions, brings the
piercings and solid parts of them, coincident, and before the exposure aperture, by a
single and simultaneous motion, whereby the shutter is opened and closed, and
exposure obtained, in manner, substantially as described and set forth.
Secondly-An instantaneous or time camera shutter, working or operating the
shutter plates, simultaneously, in unison, and in reverse directions, for exposure and
cutting off, for one or other, or for the both, by a pivoted beam or lever, connected
to the plates respectively, which are made thereby, in inanner, substantially as described
and set forth.
Thirdly-A camera shutter, operating or performing the shutter plates, by a
plunger, or plungers, or a piston or pistons, working within a cylinder or cylinders, or
casings, and operated upon, or worked by, compressed air or liquid, through the
intervention of an inflated, or filled, or partially filled, forcer or rubber ball, substan-
tially as described and set forth in Figures 1 to 8.
Fourthly A camera shutter, consisting of pierced and reverse moving shutter
plates, enclosing casing, rocking beam, and pneumatic operator, constructed,
arranged, and operating, substantially as, and for the purpose, as set forth, in
Figures 1 to 7.
Fifthly-A detention, or detentative time camera shutter, as described and set
forth in Figure 8, whereby the shutter is operated, and exposure obtained, by the

page_text: detention upon an inflated ball, or sphere, substantially as described and set forth in
Figure 8.
Sixthly A "Chronolux" time shutter, the construction, arrangement, and com-
bination of the parts, as described and set forth in Figure 11.
Dated this 13th day of August 1890.
WILLIAM JAMES LANCASTER.
By Henry Skerrett,
6, Livery Street, Birmingham, Agent for Applicant.