Improvements in Shutters for Photographic Cameras.
Year: 1890

page_text: Date of Application, 9th July, 1890
Complete Specification Left, 26th Mar., 1891-Accepted, 2nd May, 1891
PROVISIONAL SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
I, JOHN WILLIAM SMITH of 10 Otterburn Terrace, Jesmond, Newcastle-on-
Tyne, in the County of Northumberland, Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention has reference to a construction of shutter for a photographic
camera and means for setting and operating the same, the arrangement being such
that the shutter can be used for obtaining an instantaneous exposure, or a time
exposure, at the will of the operator.
A photographic shutter according to this invention comprises two thin circular
discs each formed with an opening preferably of elliptical form. These discs are
mounted on spindles geared together whereby they can be caused to rotate
simultaneously and in opposite directions between two fixed plates of suitable
material such as ebonite, in each of which is a circular hole, these holes being
opposite each other and of a diameter corresponding to that of the lens in the
camera. The elliptic openings in the discs are so arranged that when they cross
each other directly opposite the holes in the fixed plates an opening is produced
opposite the centre of the lens, which is speedily opened to full aperture, remaining
so until the exposure is nearly complete, when the opening again closes to the
centre.
Each disc may have a slot in it wide enough to allow the spindle attached to the
other disc to pass through it and long enough to allow sufficient turning movement
of the disc in which it is cut. By extending the spindle of one disc only through
the front plate and the spindle of the other disc only through the back plate, the
slots can be dispensed with and the two discs brought close together, one or
both of these discs being dished or recessed to receive these toothed wheels
which are placed between them and fixed to the respective spindles.
To one of the spindles which projects through the back plate, and hereinafter
called the first spindle, is attached a lever to which is fixed one end of a coiled
spring-the other end of which is fixed to a drum that can be rotated and fixed in
any desired position. Or, instead of this lever there may be fixed to the first spindle
a small toothed wheel into which gears a larger one to which one end of the coiled
spring is fastened, the other end of this spring being fastened to, and coiled around,
a drum riding on the same spindle as the larger wheel. The drum is capable of
being turned to wind up the spring and then fixed in any position, so that the
tension of the spring and the consequent time of exposure can be regulated to suit
requirement.
To the end of the first spindle, projecting through the front plate, is fastened a
milled head for setting the shutter, and also a projecting piece or catch which
engages a notch formed in a releasing lever pivoted to the front plate. When the
spring is wound up, if the releasing lever be raised, the catch will be released and
the discs will be caused to rapidly revolve in opposite directions by the action of the
spring.
The releasing lever may be released directly by hand, or by a pneumatic releasing
device. In the latter case, a small knee or bracket is fastened to the front plate of
the shutter, and between this plate and a projecting piece fastened to the free end
of the releasing lever, is placed an india rubber bellows connected by a tube to an
air ball, as well understood. The end of the releasing lever is kept pressed towards
the knee piece or bracket by means of a suitable spring.
For obtaining "time" exposures the following construction is adopted. To the
front or outer end of the second or driven spindle is attached a small disc to which

page_text: is fixed a pin arranged to engage with a short catch lever pivoted upon the same
spindle. To the releasing lever is pivoted another lever, (hereinafter called a
stopping lever) in one end of which is a slot in which works a pin secured to the
front fixed plate; or the stopping lever may be pivoted to a pin on the front plate
in which case it is connected to the starting lever by a pin and slot connection. The
other end of the stopping lever is formed with a projection which, when the shutter
is set for time exposure, engages with the free end of the catch lever when the two
revolving discs are in positions in which they uncover the lens. The free end of the
catch lever can move past the end of the stopping lever when the latter is in its
normal position. For a time exposure the catch lever is turned upwards until it
passes the free end of the stopping lever, the shutter being set as before. When the
air ball is compressed the free end of the releasing lever is raised as also is the free end
of stopping lever. The releasing lever consequently releases the projecting piece or
catch on the first spindle and the two discs are allowed to revolve until the lens is fully
uncovered when the pin on the small disc of the second spindle will engage the catch
lever and causes the same to engage with the projection on one end of the stopping
lever and will arrest the motion of the discs. This lever comes to rest on the india rubber
bellows which forms an air cushion that serves to decrease vibration to a minimum.
The lens will be kept uncovered so long as the air ball remains compressed but
immediately the pressure is removed the discs will continue their motion and recover
the lens.
According to a modified arrangement the coiled spring is dispensed with and the
larger of the toothed wheels is provided with two pins placed at a suitable distance
from the centre of the wheel and jointed to two connecting rods the ends of which
project slightly beyond the edge of the shutter so as to be capable of being operated
by hand. By pressing the one or the other of these rods, the discs are revolved
and the exposure made, the shutter being at the same time set for the next exposure.
According to another arrangement I use a coiled spring tightly wound upon a
drum and from each of the revolving discs with two or more openings, so that by
means of a suitably shaped lever placed preferably on the front plate, a series of
exposures can be made without the necessity of resetting the shutter for each
exposure. The lever is formed with two notches, or it may carry two pins which
engage alternately with a projecting piece fastened to one of the spindles which
carry the revolving discs. A rod arranged to be reciprocated may be used instead
of this lever.
This ach do of Lulu. 1900
W. LLOYD WISE,
Per F. J. Brougham.
COMPLETE SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
I, JOHN WILLIAM SMITH, of 10 Otterburn Terrace, Jesmond, Newcastle-on-
Tyne, in the County of Northumberland, 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 :-
This invention has reference to an improved construction of shutter for a photo-
graphic camera with means for setting and operating the same, the arrangement
being such that the shutter can be used for obtaining an instantaneous exposure, or
a time exposure, at the will of the operator.
A photographic shutter according to this invention comprises two thin circular
dises each formed with an opening preferably of elliptical or nearly elliptical form.
These discs are mounted on spindles geared together whereby they can be caused to
rotate simultaneously and in opposite directions between two fixed plates of suitable
material such as ebonite in each of which is a circular hole these holes being opposite

page_text: each other in line with the lens of the camera and of a diameter corresponding to
that of the lens in the camera. The elliptic openings in the discs are so arranged
that when the discs are allowed to rotate and the said openings pass each other an
opening is produced directly opposite the holes in the fixed plates and in line with
the centre of the lens, which opening speedily increases to full aperture, remaining
so until the exposure is nearly complete, when the opening is again closed in line
with the centre of the lens.
The accompanying drawings show how my invention may be conveniently and
advantageously carried into practice.
Fig. 1 being a front elevation of my improved shutter.
Fig. 2 a rear view thereof modified as hereinafter described as respects the rotating
mechanism which is shewn in longitudinal central section.
Fig. 3 a plan corresponding to Figure 2.
Fig. 4 a shutter with a modification of operating mechanism I sometimes adopt.
Fig. 5 a plan of the apparatus illustrated in Fig. 4.
Fig. 6 another modification of operating mechanism and
Fig. 7 a further modification.
The
A represents the outer casing of my improved shutter comprising two fixed plates
each of which has formed therein the openings or apertures B one of the plates
being arranged at the front and the other at the rear of the shutter.
openings B are situated immediately opposite and with their axes in line with
that of the lens of the camera. CC represent the revolving discs hereinbefore
referred to in which are formed the elliptical or nearly elliptical openings C¹.
These discs as shown in Figs. 1 and 3 are mounted upon suitable spindles D which
extend through both the front and rear plates of the casing A, each of the discs
being provided with a concentric segmental slot or opening E through which the
spindle of the other disc passes, these slots or openings being of sufficient extent
to permit the necessary degree of motion of the respective discs. The discs are
caused to rotate simultaneously and synchronously by means of a pair of similar
toothed wheels F engaging with one another and mounted one on the spindle of one of
the discs and the other on the spindle of the other disc.
I may however in some cases instead of employing spindles which project through
both of the discs, employ short spindles one of which is supported in the front
and the other in the rear plate of the shutter these spindles extending only about
halfway across the said shutter and each having secured thereto one of the said
discs. I thus avoid the necessity for forming the slots E in the discs. The said
short spindles are in this case geared together by a pair of toothed wheels mounted
upon the extremity of each in the space between the revolving discs as shown in
Figs. 4 and 5 which discs may be soniewhat dished near their centres to allow space
for the said toothed wheels.
To one of the spindles D which projects through the back plate of the casing A
and which is hereinafter called the first or motor spindle by reason of its imparting
motion through the toothed wheels F to the other spindle is attached a lever or
projection to which is secured one end of a coiled spring contained in a drum to
which the other end of the said spring is fixed this drum being so arranged that it
can he rotated and fixed in any desired position. Or instead of this lever there
may be fixed to the first spindle a small toothed wheel G as shown in Figs. 4 and 5
with which gears a larger toothed wheel G' to which one end of the coiled spring
is secured, the other end of this spring H being connected to, and coiled around a
rotary drum H' mounted on the same spindle as the larger wheel. The drum is
capable of being turned to wind up the spring and then fixed in any position, by
the engagement of a detent or pawl I under the influence of the spring I with the
toothed wheel I' the said pawl being connected to the casing of the shutter so that
the tension of the spring and the consequent time of exposure can be regulated to
suit requirement.
On the other end of the motor spindle, projecting through the front plate is
provided a milled head J for setting the shutter and winding up the aforesaid spring

page_text: by rotating the discs C until a projecting piece or catch D¹ engages in a notch
formed in a releasing lever K pivoted to the front plate or to a carrier plate fitted
upon the same. When the spring is wound up, if the releasing lever be raised, the
said catch will be released and the discs will be caused to rapidly revolve in opposite
directions by the action of the spring. The position of the openings or apertures C¹
is so arranged that they commence to pass one another immediately in line with the
centre of the lens and being of the same dimensions and moving at the same speed
they consequently complete their passage at the same point, the uncovering and
covering of the lens thus taking place from the centre of the said lens towards the
circumference and from the circumference towards the centre, respectively.
The releasing lever K may be released directly by hand, or by a pneumatic
releasing device.
In the latter case, a small knee or bracket K¹ is secured to the front plate of the
shutter, and between this plate and a projecting piece fastened to the free end of
the releasing lever is placed an india rubber bellows connected by a tube to an
air ball so that by compressing the said air ball the bellows will be inflated and the
releasing lever K thereby raised and the catch D' disengaged as will be readily
understood. The end of the releasing lever is kept pressed towards the knee piece
or bracket by means of a suitable spring K
For obtaining "time" exposures I find it advantageous to adopt the following
construction. Near the front end of the second or driven spindle D is attached a
small disc L to which is fixed a pin L' arranged to engage with a short catch
lever D² mounted somewhat loosely upon the same spindle. To the releasing
lever K is pivoted another lever M (hereinafter termed the stopping lever) in one
end of which is a slot M¹ adapted to receive a pin M² secured to the front of the
casing of the shutter; or the stopping lever M may be pivoted to a pin or stud on
the front plate and connected to the releasing lever K by a pin and slot connection
or other suitable joint. The other end of the stopping lever is formed with a catch
or projection which, when the shutter is arranged for a time exposure is adapted to
engage with the free end of the above mentioned catch lever D² when the two
revolving discs are in the position in which they uncover the lens. The free end
of the catch lever can move past the end of the stopping lever when the latter is in
its normal or retired position but is for instantaneous exposures allowed to remain
in a vertical or nearly vertical position. When however a time exposure is required
the catch lever D2 is turned upwards past the free end of the stopping lever M until
it occupies the position shewn in Fig. 1 the shutter being set as before. When the
air ball of the pneumatic releasing device is compressed the free end of the releasing
lever is raised and this movement it will be readily seen effects the simultaneous
raising of the free end of the stopping lever. The releasing lever consequently
releases the projecting piece or catch D' on the first or motor spindle and the two
discs are allowed to revolve until the lens is fully uncovered at which point the
aforesaid pin L' on the small disc L of the second spindle is arranged to engage the
catch lever D thereby causing the same to engage with the projection on one end
of the stopping lever M and arresting the motion of the discs. This lever comes to
rest on the india rubber bellows which serves to reduce the shock or vibration to a
minimum. The lens will thus be kept uncovered and the exposure will be continued
as long as the air ball remains compressed but immediately the pressure is removed
the levers will be allowed to fall and the catch D' being disengaged the discs will
complete their motion and again close the aperture and cover the lens.
According to a modified arrangement which I sometimes employ the coiled
spring is dispensed with and the larger of the toothed wheels iz. the wheel Gis
provided with two projecting pins or studs G situated at a suitable distance from
the centre of the wheel and each connected to one of two connecting rods N
(Fig. 7) the ends of which project slightly beyond the edge of the shutter so as to
be capable of being operated by hand. It will be seen that when one of the rods N
is in its uppermost position, or projecting furthest from the shutter the other
rod is in its lowest or innermost position, and the parts are so arranged that when

page_text: the rods N are at the extremity of their movement, the discs C¹ have similarly
completed their movement and are ready for the next exposure. Thus by depressing
the uppermost of the rods N (Fig. 7) the wheel G¹ is caused to rotate and through
the medium of the small wheel G causes the discs C to travel from one extremity
to the other of their movement, thereby effecting a complete exposure and covering
the lens again, so that when the other rod N which has been raised by the movement
of the disc G' is in its turn depressed the discs will be moved in the reverse direction
and another complete exposure effected. Thus by pressing the one or the other of
these rods, the discs are revolved and the exposure made, the shutter being at the
same time set for the next exposure.
Instead of employing a spring which requires to be set for each exposure I may
employ in connection with the arrangement shewn in Fig. 5 a coiled spring similar
to the spring H but which can be wound up so as to effect a considerable number
of revolutions of the disc C. In this case in place of the arrangement of releasing
lever K and catch DI employ a device such as that shewn in Fig. 6 which is
designed to act as an escapement to permit the discs to revolve through the space
of half a revolution only at one time under the influence of the aforesaid springs,
and thereby to effect a single exposure for each operation of the device.
For this purpose I arrange a sliding bar O which is adapted to move to and fro
in suitable supports or brackets o' secured to the casing of the shutter, a spiral
spring of being provided which acts on the bar O and normally causes the extremity
of the same to project beyond the edge of the shutter as shown in Fig. 6. The said
bar Ois provided between the brackets O' with a curved or bent central
portion into which the spindle of one of the discs projects, this bent portion
being sufficiently wide to permit of the sliding bar moving to and fro without fouling
the said spindle.
On the extremity of the spindle a pair of projections or engagement pieces P, P₂
are provided, and on the sliding bar O are provided a pair of pins or projections P1, P2
which are so situated that when the said bar is at either extremity of its movement
one or other of the said pins will project into the path of the engagement pieces P, P³.
The aforesaid actuating spring being wound up therefore, and the parts being in the
position shown in Fig. 6 it will be seen that by pressing the sliding bar O inwards,
the projection P which is in engagement with one of the pins P' will be disengaged
and the spindle will be allowed to rotate until the said projection engages with the
pin P which has been carried toward the left by the movement of the bar O, so
preventing further rotation until the bar O is allowed to move outward again, when
the spindle will be caused to complete its half revolution and the parts will be
restored to the position shown in Fig. 6. Thus by simply moving the bar O inwards
and outwards the operator can effect an exposure and restore the parts of the
shutter to their original position, and this may be repeated for as many successive
exposures as may be wished, provided the spring is not allowed to run down.
Another arrangement for actuating the discs C is shown in Figs. 2 and 3.
According to this arrangement the first or motor spindle is provided with a small
pulley or grooved wheel Q and around this is wound a cord or band of cat-gut or
other suitable material the free end of which is connected to a sliding piece or
cylinder R which is caused to slide within a cylinder or guide S by an internal
spring R' which bears at one extremity against an adjustable piston T or the like,
its other extremity pressing upon the end of the cylinder R. The piston T is made
adjustable by being secured on the extremity of a screw threaded rod T¹ the screw
threaded portion of which works in a nut U which is restrained from end wise
motion but is provided with or connected to a milled head U', so that by rotating
the said nut by means of the milled head, in one or the other direction the piston T
can be caused to move towards or away from the end of the cylinder against which
the spring bears, thereby increasing or diminishing the tension of the said spring
and conversely diminishing or increasing the time of the exposure. An indicator V
is rigidly secured upon the rod T¹ and projects through a slot V' the edge of which

page_text: is graduated. The position of the indicator V thus corresponds with the com-
pression of the spring, and the graduations of the slot V' are arranged to show the
proper positions of the indicator for obtaining exposures of different lengths. - In
order to effect an exposure the discs C are turned round until the catch D (Fig. 2)
engages with the notch in the releasing lever which is preferably similar to that
shown in Fig. 1. In the turning of the discs the cat-gut cord is wound on the
pulley Qand draws the sliding cylinder R back, compressing the spring. R'. On
the operation of the releasing lever, the cylinder R which has been restrained from
motion by the cat-gut cord springs forward and draws the said cord off the pulley Q
thereby rotating the same and causing the discs C to revolve and give the required
exposure.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is
1. A shutter for a photographic camera comprising two discs adapted to be
rotated simultaneously in opposite directions and each having an opening therein
the two openings being so arranged that during the rotation of the discs they pass
one another and effect the required exposure in the manner set forth.
2. In a shutter of the kind referred to in the preceding claim for a photographic
camera the arrangement of the dises in such manner that the openings therein shall
when the discs are rotated commence to pass one another and also terminate their
passage in line with the centre of the lens as hereinbefore described for the purpose
specified.
3. In a shutter for a photographic camera the combination with the discs C
provided with the openings C' and the slots E, of the catches D' the pin L' the
releasing lever K and the stopping lever M arranged and operating substantially as
herein before described for the purposes specified.
4. A shutter for a photographic camera comprising a pair of discs C having
apertures C therein and provided with mechanism for rotating the same simul-
taneously in opposite directions whether such mechanism be constructed and arranged
according to Fig. 1 or to Figs. 2 and 3, to Figs. 4 and 5, to Fig. 6 or to Fig. 7 of
the accompanying drawings.
5. The combination and arrangement of parts described with reference to Fig. 1
for the purpose specified.
Dated this ofth dow of March 1901
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.