IMPROVEMENTS IN INSTANTANEOUS PHOTOGRAPHIC CAMERA SHUTTERS
Year: 1885

page_text: I, WILLIAM JAMES LANCASTER trading as J. Lancaster and Son of Colmore Row,
Birmingham, in the County of Warwick, Optician, do hereby declare the nature
of said invention for "IMPROVEMENTS IN INSTANTANEOUS PHOTOGRAPHIC CAMERA
SHUTTERS," to be as follows:-
My invention relates to expedients or means for pre-determining the amount or
duration of exposure that shall be allowed in photographic operations; that is, the
amount of exposure or length of time that the camera shutter shall be open, can be
increased or decreased at pleasure, so that the duration of exposure can be pre-
determined to the greatest possible nicety according to the varying requirement of
the operator, by increasing or decreasing the velocity with which the shutter is
opened and closed, in carrying out what is commonly known as instantaneous
photography.
In carrying out my improvements, I proceed as follows.
Screwed to, or connected to the front of the camera lense, is a cap having within
its middle the exposure aperture through which light passes. This cap has upon
its front a depending or hanging bracket plate which carries the shutter, catch,
releasing and other appliances, so that the exposure aperture through the cap is
situated near the top of the bracket plate. The rotating shutter turns axially
upon a pivot in front of, and within the said bracket plate, which said shutter has
a semicircular opening nearly running in the direction of a diameter which comes
in front of the cap aperture when exposure is required. The other part of the
shutter is unpierced or solid. On the fixed part of the bracket plate is a stud or
stop against which a projecting piece on the movable shutter comes, in limiting its
motion; and upon the lower part of the bracket frame, is a toothed quadrant or
sector, which carries a long curved arm, and to the end of this arm the spring for
rotating the shutter is connected; thus the spring for giving the required movement
or velocity, is connected to the end of the arm before named, and to the shutter,
preferably by means of a standing out stud. A pawl or catch engages with the
toothed quadrant, which pawl is kept in position by a spring. The shutter has
cut within or upon its periphery two or more notches, into which the nose end of
a jointed lever takes for holding the shutter in position with respect to the
exposure aperture. The holding and releasing lever is pivotted preferably near the
top of the bracket plate; and under the operating end of the said last named lever
'

page_text: is a thumb-rest, and between this thumb-rest and the underside of the lever, is a
spring for automatically pressing the nose of the catch into one or other of notches
in the edge of the shutter.
To operate the instantaneous shutter I proceed as follows after having determined
the amount of exposure required. The spring tension lever is then moved out-
wardly upon its joint for giving the requisite tension to the spring, and so
incidentally increasing the velocity of the shutter. Thus, the teeth of the toothed
sector on the jointed end of the lever, are simply graduations into which the pawl
engages, for holding the lever at determinate distances, with respect to the spring's
connection with the shutter. The changing of the lever's position, determines the
velocity with which the shutter shall be rotated, and consequently the amount of
exposure.
The shutter is set or adjusted by moving outwards the adjustment lever, and
rotating the shutter nearly through a complete rotation, or until the stop arm on
the shutter comes against the offside of the fixed stop on the bracket plate. The
spring having been distended and the shutter closed and fixed by the nose of the
fixing lever, all is now ready for exposure, which is effected by simply pressing
the end of the fixing lever, when its nose end is raised from the notch in the shutter,
which latter now rapidly revolves by the tension of the spring, and the necessary
exposure given by the opening in the shutter becoming momentarily coincident
with the hole in the cap in front of the lense.
Instead of having ratchet teeth on the end of the arm, the angle of the arm may
be determined and fixed by a screw, or the length of the arm may be shortened or
lengthened, so as to give the necessary tension to the spring by sliding inwards.or
outwards and fixed by a catch or screw clamp. A graduated scale may if necessary
be placed on the bracket plate for determining the angle or position of the lever.
Dated this Twenty ninth day of April 1885.
.

page_text: Improvements in Instantaneous Photographic Camera Shutters.
I, WILLIAM JAMES LANCASTER trading as J. Lancaster & Son of Colmore Row
Birmingham, in the County of Warwick Optician, do hereby declare the nature of
said invention for "IMPROVEMENTS IN INSTANTANEOUS PHOTOGRAPHIC CAMERA
SHUTTERS," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:--
'
My invention relates to expedients or means for pre-determining the amount or
duration of exposure that shall be allowed in photographic operations; that is, the
amount of exposure or length of time that the camera shutter shall be open, can be
increased or decreased at pleasure, so that the duration of exposure can be pre-
determined to the greatest possible nicety according to the varying requirement of
the operator, by increasing or decreasing the velocity with which the shutter is
opened and closed, in carrying out what is commonly known as instantaneous
photography.
In carrying out my improvements, I proceed as follows.
Screwed to, or connected to the front of the camera lens, is a cap having within
its middle the exposure aperture through which light passes. This cap has upon
its front a bracket plate, which carries the shutter, catch, releasing and other
appliances, with the exposure aperture through the cap situated near the bottom
of the bracket plate. The rotating shutter turns axially upon a pivot in front of,
and within the said bracket plate, which said shutter has a semicircular opening
nearly running in the direction of a diameter which comes in front of the cap
aperture when exposure is required. The other part of the shutter is unpierced or
solid. On the fixed part of the bracket plate is a stud or stop against which a
projecting piece on the movable shutter comes, in limiting its motion; and upon
the lower part of the bracket frame, is a toothed quadrant or sector, which carries
a long curved arm, and to the end of this arm the spring for rotating the shutter
is connected; thus the spring for giving the required movement or velocity, is
connected to the end of the arm before named, and to the shutter, preferably by
means of a standing out stud. A pawl or catch engages with the toothed quadrant,
which pawl is kept in position by a spring. The shutter has cut within or upon
its periphery two or more notches, into which the nose end of a jointed lever takes
for holding the shutter in position with respect to the exposure aperture. The
holding and releasing lever is pivoted preferably near the top of the bracket plate;
and under the operating end of the said last named lever is a thumb rest, and
between this thumb rest and the underside of the lever, is a spring for automatically
pressing the nose of the catch into one or other of notches in the edge of the
shutter.
To operate the instantaneous shutter I proceed as follows; after having
determined the amount of exposure required. The spring tension lever is then.
moved outwardly upon its joint for giving the requisite tension to the spring, and
so incidentally increasing the velocity of the shutter. The teeth of the toothed
sector on the jointed end of the lever, are simply graduations into which the pawł
engages, for holding the lever at determinate distances, with respect to the spring's
connection with the shutter. The changing of the lever's position, determines the
velocity with which the shutter shall be rotated, and consequently the amount of
exposure.
The shutter is set or adjusted by moving outwards the adjustment lever, and! (
rotating the shutter nearly through a complete rotation, or until the stop arm on
;

page_text: the shutter comes against the offside of the fixed stop on the bracket plate. The
spring having been distended and the shutter closed and fixed by the nose of the
fixing lever, all is now ready for exposure, which is effected by simply pressing the
end of the fixing lever, when its nose end is raised from the notch in the shutter,
which latter now rapidly revolves by the tension of the spring, and the necessary
exposure given by the opening in the shutter becoming momentarily coincident
with the hole in the cap in front of the lens.
Instead of having ratchet teeth on the end of the arm, the angle of the arm be
determined and; fixed, by a screw, or the length of the arm may be shortened or
lengthened, so as to give the necessary tension to the spring by sliding inwards or
outwards and fixed by a catch or screw clamp.. A graduated scale may if necessary.
be placed on the bracket plate for determining the angle or position of the lever.
I will now proceed to describe with reference to the accompanying drawing, the
manner in which the same is to be performed.
Figure 1 is a front elevation of an instantaneous photographic camera shutter,
constructed according to my invention, the said shutter being adjusted and in
position for instantaneous exposure on the pressing down of the catch lever, which.
holds the rotating shutter which is under tension, by the pull of an elastic or other
spring. Figure 2 is the same, after the shutter has been rotated, and the exposure
aperture momentarily allowed to be uncovered. The catch lever is shown.
depressed, or in a position which it would assume, on the liberation of the shutters
for instantaneous exposure. Figure 3 is a back elevation of figures 1 and 2,
showing the exposure aperture and, cap, a portion of the bracket plate also being
removed, for the purpose of showing the means whereby the lever (for giving
greater or less tension to the elastic or yielding cord by which the shutter is
rapidly rotated) is fixed or adjusted in position. Figure 4 is a side elevation:
partly in section. Figure 5 is an edge view of figure 2. Figure 6 is a side view
of spring and figure 7 is a front view of the lever or arm.
The same letters of reference indicate corresponding parts in the several figures
of the drawing.
a is a cap, having within its middle an aperture a through which light passes
when uncovered by the rotating shutter b. This said cap has upon its front a
bracket plate c which carries the shutter ring b¹, releasing and fixing lever catch d,
and rest e, between which the spring f is situated and is compressed, on the raising
of the lever upon its fulcrum centre.
The rotating shutter 6 turns or rotates upon a pivot g, in front of the said-
bracket plate, which said shutter is also provided with a semi circular opening b²,
which runs in a direction of a diameter of the shutter. This aperture on becoming
coincident with the exposure aperture in the middle of the cap, allows the light to
pass there-through, for the time being. The other part of the shutter is unpierced.
h is a stop against which the finger, or projection 6° comes; for limiting the
motion of the said shutter.
The shutter b has upon its edge, at nearly opposite points, catch depressions 6*65.
The latter. b is the one wherein the nose d' of the lever d takes and engages
therein, when the shutter is in a position to be rotated, for instantaneous exposure.
The former catch depression 64 is for keeping or retaining the shutter aperture
coincident with the exposure aperture, when focussing. i is a quadrant lever,
jointed upon a centre . This curved lever has upon its joint underside, toothed
depressions or teeth is wherein a detent or tooth j carried by a spring k, takes and
engages. The tooth or detent j is liberated from one or other of the radial teeth 2³
by the pusher k² working through a hole in the bracket plate c. I is a spring or
elastic band, connected at one end to the necked stud be on the shutter b, while the.
other end, is connected to the terminal end of the arm i. This band when under
tension, gives the required rotary movement or velocity to the shutter, when
liberated, on the distension of the spring or band around the stud and pivot centre
ping, as seen in figure 1,

page_text: The arm i is capable of opening out, as represented in the dotted lines figure 1,
so as to give greater tension to the spring or band and consequently increased
velocity to the shutter, the velocity being accelerated or diminished according to
the distance between the end and the stud be when the shutter is in the position
as represented in the said figure 1.
To operate the instantaneous shutter after it has been determined what amount
of exposure will be required, place the parts in the position as represented in
figure 1. The spring tension lever is then moved outwardly upon its joint, giving
the requisite tension to the spring, imparting the requisite velocity to the shutter.
The lever is held in its distended position, by the teeth on its underside, engaging
with the tooth on the spring plate k.
The shutter now being set or adjusted, the tail end of the fixing lever is raised,
when its nose or hooked end, is lifted from the notch or depression 6³, when the
shutter is rapidly rotated, by the tension of the spring, and the necessary exposure
thereby given, by the opening in the shutter becoming momentarily coincident with
the hole in the cap in front of the lens.
The tension regulating lever i, is brought back, by pressing the stud k², which
removes the tooth or detent j, from the teeth i³, thus allowing the said arm, to be
placed in any backward position.
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 photographic camera shutter consisting of a partially
pierced disc (called a shutter) which rotates or turns within an enclosing ring, and
upon a central pivot or axis situated in the middle of a bracket carrying plate.
The disc or shutter is operated or rotated by a spring or elastic band, one end of
which is connected to the shutter and the other connected to a pin or stud situated
either on the end of an arm or upon any other convenient part outside the shutter,
while the middle part is twisted or partially turned round (when under tension) the
head of the central pivot. The shutter is detained, when under the influence of
the spring in two or other positions by notches or catch depressions situated at
nearly opposite points in the edge or periphery of the disc or shutter; in which
depressions the hooked end of a lever engages. The liberation or the letting go of
the shutter is effected by the raising of the tail end of the said lever, so as to
disengage its other end from one of the two holding catch depressions in the
shutter, the shutter's motion being limited by a stop, substantially as described
and illustrated.
Secondly. Increasing or decreasing the tension of instantaneous shutter springs
or bands (for accelerating or decreasing the velocity of the said shutter) by means
of an arm, opening outwards or closing inwards, and pivoted at one end, and
carrying at its other end, an elastic band or spring, which is connected to the
shutter; the position of the arm being determined and fixed by the joint end
having upon its under side teeth or serrations wherein a tooth of a spring catch
engages, the said tooth being liberated, by a pusher, when the arm is required to
be drawn inwards substantially as described and illustrated; also fixing or changing
the position of the lever arm by a screw or clamp substantially as described.
Dated this Twenty seventh day of January 1886.