Year: 1886

page_text: Date of Application, 23rd July, 1886.
Complete Left, 23rd Apr., 1887.
Complete Accepted, 24th May, 1887.
I, WILLIAM JAMES LANCASTER of Colmore Row Birmingham in the County of
Warwick, Manufacturing Optician do hereby declare the nature of this invention to
be as follows:-
My invention relates to instantaneous photographic camera shutters for effecting
what is generally known as instantaneous exposure, whereby light is allowed only to
pass momentarily through the lens or exposure aperture; and my said invention
consists essentially of a fantail shaped shutter, hung or pivoted above the exposure
aperture, and before which aperture, the said shutter is flirted or rotated from right to
left by means of a volute spring, secured at one end to the fixed axis or frame, and at
the other end to the shutter. The speed or velocity of the shutter is adjusted and
determined by means of an adjustable device in the form of a face ratchet, and spring
pawl.
In carrying out my invention, the frame of the shutter is made of two parts or
plates preferably of the shape of the shutter, which is the segment of a circle or of the
shape of a fantail; and between these plates the shutter works, which is pivoted
above the exposure aperture which is situated at the lower or widened out part of the
frame.
The motion of the shutter is limited by a midway projection or stop situated on its
underside edge which comes against a middle stop on or carried by the frame. These
stops limit the motion or flirting of the shutter beyond a certain point, which said
point determines the closing of the aperture, so that the two stops come together only
at a time, when the shutter is before the aperture.
Around the pivot or pin upon which the shutter is hung, a volute or coiled spring
is wound and secured thereto at one end, and at the other end to the shutter.
The velocity of the shutter is determined by increasing or decreasing the tension of
the spring, by closing the coils closer upon each other, or relaxing them according to
the velocity required. The spring has always an acquired tension by the spring being
under tension before adjustment.
The means of adjustment consist of a face ratchet wheel with a spring detent
engaging with the teeth thereof, and to this wheel one end of the spring is connected

page_text: while the spring detent is connected to the other or fixed part, so that in order to vary
the tension of the spring, for increasing or decreasing the velocity of the shutter, it is
only necessary to move round the wheel, (or an equivalent in the form of a slide) by
a small lever or handle, when the coils of the spring are made to close upon, or
recede from each other, thereby increasing or decreasing the tension, and power
thereof.
Instead of employing a volute or ribband spring as described, a rubber band or a
flat spring, (the latter acting upon a pin) may be employed instead.
The shutter is liberated by means of a spring detent or catch which fixes the shutter
for a time in an acquired state of tension for exposure.
For a single exposure, adjust the speed or tension device of the spring, according
to the length of time that the shutter shall be allowed to make, during its motion from
right to left; this done, the spring lever detent which holds the shutter is then pressed,
when the shutter is released, and the shutter flirted momentarily from before the
aperture, making nearly a complete circle, described from the pivot centre on which
it turns, its motion being arrested and the aperture closed by the stop of the ono
coining against the stop of the other.
The holding lever detent is self-acting; so that on the shutter being brought round
to its acting position, its end snaps into a holding notch which keeps the shutter
in position.
WILLIAM JAMES LANCASTER.
By Henry Skerrett,*
6, Livery Street, Birmingham,
Agent for the Applicant..

page_text: Improvements in Instantaneous Photographic Camera Shutters.
I, WILLIAM JAMES LANCASTER of Colmore Row Birmingham in the County of
Warwick 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 :-
My invention relates to instantaneous photographic camera shutters for effecting
what is generally known as instantaneous exposure, whereby light is allowed only to
pass momentarily through the lens or exposure aperture; and my said invention
consists essentially in employing an excentric shaped shutter, hung or pivoted above
the exposure aperture, and before which aperture, the said shutter is flirted or partially
rotated, from right to left, by means of, or through the influence of a volute spring,
secured at one end to a turning axis, and at the other end, to the shutter or to an
enclosing casing carried by the shutter.
The spring is kept in a varying degree of tension, by a ratchet wheel and pawl.
In carrying out my invention, the frame of the shutter is preferably made in two
parts, or of two plates, somewhat of the shape of a fantail, or the segment of a circle;
and on the outside or upper plate, the shutter works, and which shutter is pivoted
above the exposure aperture, situated at the lower or widened out part of the
frame.
and a
Around the pivot pin or axis upon which the shutter is hung, is a volute or coiled
spring, secured at one end to the axis, and at the other end to an enclosing case
carried by and upon the front face of the shutter.
A suitable catch, holds the shutter in position, until exposure is necessary,
stop or stops limit the shutter's motion, when it is flirted or rotated.
The shutter's velocity is determined, by closing the coils of the spring more or less
upon each other, and so increasing or decreasing the tension according to the velocity
or speed which the shutter is required to be flirted in front of the exposure
aperture.
The spring is kept at any determinate tension after winding or coiling, by a lever
pawl and spring, the former engaging with the teeth of a ratchet wheel.
Instead of employing a volute or ribband spring as described, a rubber band, or a
flat spring (the latter acting upon a pin) may be employed.
To work the shutter, first adjust the spring to the speed required, or to the length
of time that the shutter shall be made to take, in passing over the exposure aperture,
the shutter is then turned into its normal position, and held there, by a spring lever
catch, which on being released therefrom, is momentarily flirted from in front of the
exposure aperture and back again, making the exposure longer for the foreground or

page_text: lower part of the picture, than for the sky, which is an advantage in landscape
photography.
I will now proceed to describe with reference to the accompanying Drawing, the
manner in which the same is to performed.
Figure 1 represents in front elevation, an instantaneous photographic camera
shutter made according to my invention. The shutter is shown held in position for
use, which on being liberated, by pressure applied to the lever catch, it is flirted
momentarily from in front of the exposure aperture and back again into the position
as represented in figure 2. Figure 3 represents how the shutter first exposes and
gradually uncovers the lower portion, or lower part of the exposure aperture, before
the upper half, so as to thereby give a longer exposure to the said lower part, than
that of the upper part. Figure 4 represents in back elevation, with the back covering
plate removed, and figure 5 is a vertical section of the said shutter, upon the dotted
lines A B figure 1.
The same letters of reference indicate corresponding parts in the several figures.
a is the principal or carrying frame of the shutter, with a supplementary frame a
at its back, for covering up the adjustment means, interposed between the front and
back plates a, a² a³ is the exposure aperture, situated at the lower, and broadened
out part of the said frame. b is an excentrically hung shutter, turning and working
upon a pin or centre c, and in consequence of being so hung, uncovers and recovers
the aperture a³ in a graduated or progressive manner, viz. it uncovers the apertures
progressively from bottom to top, and then recovers it from top to bottom, on the
shutter's change of position from figure 1 to that of figure 2.
The shutter is held in position ready for use, by an arm or stop 62, which engages
with a snug or ear d³, of an automatic lever catch d, which is free at its outer end,
and secured at its other end, to the bottom or underside of a quadrant rib or raised
part a, carried by, or at the bottom of the front plate of the frame a. e is a stay or
rest, for the taking hold of the said automatic lever for releasing the shutter. fis a
spring clip or friction device, for gradually retarding the shutter's motion, on the
arm thereof, approaching the end of the shutter's traverse or motion. The said arm
passes between the underside of the spring clip (which is bent downwards) and the top
face of the part at as shown in figure 2, thereby preventing the shutter from being
suddenly stopped, and without shock to the camera.
The means for rotating the shutter, and imparting thereto, the varying velocity as
may be required, is accomplished, by a volute spring g (as seen in figures 3 and 5)
secured at its inner end, to the movable axis c; and at its outer end to the inside part
of the enclosing cap or case h. The outer end of the said axis c is wormed, and upon
which a milled head i, by which the spring is wound up or coiled, screws; and
between the front face of the case h, and the milled turn or head i, a flat binding
spring is interposed.
Secured on the axis, and working at the back of the front plate of the frame, is a
ratchet wheel (see figures 4 and 5) and short arm k³, the latter of which, forms a
limiting stop, and prevents the overwinding of the spring; and engaging with the
teeth of the said ratchet wheel, is a lever pawl l, jointed at P, and pressed home, or
into its acting position, by a spring m.
n is a movable safety stop for preventing the shutter from being accidentally.
released, or for preventing the shutter from being again closed, when the said shutter
is required for long exposure photography.
The shutter instead of being of the circular figure as represented, it may be made in
the form of a fantail, with a raduisly curved bottom, so as to uncover and recover the
exposure aperture, in the same manner as already described.
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 excentrically hung or pivoted instantaneous photographic camera
shutter, or shutter plate,, which when partially, rotated, or turned, uncovers and
recovers the exposure aperture, progressively from bottom to top, and vice-versa;

page_text: thus giving to the bottom of the said aperture, or to the foreground or ground work
of the picture, a longer exposure than the other or upper part, substantially as
described and illustrated.
Secondly-In automatic holding and releasing catch lever mechanism, consisting
of a spring arm d, ear or snug d³ on the said arm, and rest e, (carried by the shutter
frame) in combination with the short arm 6* of the shutter, substantially as described
and set forth.
Thirdly Operating, turning or partially rotating shutters, or shutter plates, by a
volute or evolved spring, secured at its inner end to a movable axis, (or its equivalent)
and at its outer end to the shutter, or an enclosing. case carried by the shutter; and
which said spring, is wound up, and secured at the desired tension, for giving the
requisite or time exposure, by a screwed turn, ratchet wheel, stop, lever pawl and
spring. The parts being arranged, combined and acting in the ways, and for the
purpose, substantially as described and set forth.
Fourthly Arresting without shock, the motion of camera shutters, by means of a
flat or coiled spring, against which an arm on the camera shutter, strikes or impresses,
substantially as set forth.
⋅
Fifthly The improvements in the construction of instantaneous photographic
camera shutters, and the arrangement and combination of the parts of the said shutters,
as hereinbefore described and set forth in the several figures of the Drawing.
Dated this Sixth day of April 1887.