An Improved Time and Instantaneous Roller-blind Shutter for Photographic Purposes.
Year: 1896

page_text: Date of Application, 17th June, 1896
Complete Specification Left, 17th Mar., 1897-Accepted, 17th Apr., 1897
PROVISIONAL SPECIFICATION.
An Improved Time and Instantaneous Roller-blind Shutter for
Photographic Purposes.
HENRY PERCY TATTERSALL, of 58, Ainsworth Street, Blackburn, in the
County of Lancaster, Scientific Instrument Maker do hereby declare the nature
of this invention to be as follows:-
I make the external case in the form of a metal box,-there being two rollers
placed in parallel axes at either end, one having a motive spring with a knob
outside the aforesaid box, in order to decrease or increase the tension.
The other roller serves to wind the blind,-which I prefer to make of thin
macintosh, at the other end. This roller is provided with a projecting knob to
which two lugs each engage against a spring provided with two lugs. This spring
is pivoted at one end so as to have a lateral motion in addition to a rising movement.
The lateral motion is controlled and actuated by an eccentric with a small lever
attached, the object of this being to provide for the time arrangement of the
shutter, by causing the lug on the spring to engage on a lug on the end of the
revolving spindle of the roller, so as to stop its movement in the required position
to leave the aperture in the shutter uncovered. I affix on the spindle of the spring
of the roller a star-wheel and finger, so that the number of revolutions and the
tension of the spring may be observed.
Dated this 17th day of June 1896.
HENRY PERCY TATTERSALL.
COMPLETE SPECIFICATION.
An Improved Time and Instantaneous Roller-blind Shutter for
Photographic Purposes.
I, HENRY PERCY TATTERSALL of 58 Ainsworth Street, Blackburn, in the
County of Lancashire, 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 :-
The object of this invention is to provide an improved photographic shutter, for
the purpose of shutting off all light from a sensitized plate, and to enable the
operator to allow any required amount of light to penetrate the photographic lens,
and so on to a sensitised plate at wili, as I shall describe referring to the
accompanying drawings;
Figure 1 is a front view with one side of the case removed.
Figures 2 and 3 are end views shewing the parts in different positions.
I make the external case C of the shutter in the form of a box, of metal, wood,
or other suitable material, and on its back and front are certain sized openings.
In the inside of this box are mounted at the ends, two rollers A, B, having
parallel axes.
The one marked A, hereinafter called the spring roller, contains a spiral spring),

page_text: the box.
The spring is prevented from running back by a pawl P engaging a tooth of the
axis of A.
The other roller, marked B, hereinafter called the blind roller, has one end of its
axis projecting outside the box.
The dexible blind, which I prefer to make of macintosh cloth, has its ends
fastened to the rollers and has a certain sized aperture in it, at about the centre of
its length.
On the blind roller 1 place a pulley p, and attach to this a cord.
The blind is normally coiled on the spring-roller, but by pulling the cord the
blind is wound from the spring roller A on to the blind-roller B.
On the cord being released, the blind is again wound on to the spring-roller, and
in so doing, its aperture passes the openings in the sides of the box.
When the shutter is placed either before, or behind a photographic lens, and in
front of a sensitised plate; the effect of these operations is to allow the passage of
light through the lens, and on to the sensitised plate; the amount of light passing
being regulated by the tension put on the spiral spring, causing the blind to rewind
more or less rapidly.
As is not always convenient to hold the cord until a longer exposure is given,
means are provided whereby when the blind has been wound on to the blind-
roller, the cord may be released, and the blind still remain partially wound on the
blind roller with its aperture in line with the lens.
To do this, there is passed through the projecting end of the blind-roller axis, a
pin (D) and a latch stud is fixed at F on the under side of a spring lever E in such
a position as to engage this pin. When the cord has been pulled, and the blind
wound on to the blind-roller, the pin D is caught and held by the latch stud F;
the cord may then be released.
The exposure is then made by raising the spring lever E, which causes the latch
stud F to disengage from the pin D, thus allowing the blind to become wound on to
the spring roller.
It is obviously impossible to decrease the tension of the spiral spring in the spring
roller sufficiently to give a longer exposure than a fraction of a second, and, as a
much longer exposure may be required, it is necessary to provide means for
stopping the movement of the blind when the aperture is in line with the lens, so
that any required length of exposure may be given.
As described so far, there have been means provided for holding the blind wound
on the blind-roller, and for releasing same when required. The method adopted for
giving time or prolonged exposures, is as follows:-
Beyond the pin D is placed a projecting knob, or collar (G) which is provided
with two lugs; the upper one of which engages against an upper latch stud or pin F
when the spring lever E is raised.
The lower lug of G is so placed as to engage on the shorter end of the pin D.
The shutter is set by pulling the cord as before, the longer portion of the pin D
engaging on the lower stud F.
On the spring lever being raised, the lower stud F is disengaged from D and the
upper stud at F' engages with the upper lug of the collar G, and the blind is
rewound on to the spring-roller until the shorter end of the pin D is held by the
lower lug of the collar G.
This engagement is arranged to take place when the aperture in the blind is in
line with the lens.
When sufficient exposure has been given, the spring lever E is released whereupon
the blind is entirely rewound on to the spring roller.
The spring lever E is pivotted so as to have lateral as well as rising movement.
The lateral moveinent is effected by an eccentric pin at H, so that when desired,
the spring lever E may be moved aside, so far as to prevent the upper lug of the
collar G from engaging on the upper latch stud F¹.

page_text: I am aware that it has been proposed to stop the movement of the shutter midway
for lengthened exposure by means of a catch operated by gear as described in the
Specification No. 12238 of 1886, I therefore make no claim to mechanism such as
is described in that specification.
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 :--
In combination with the axis of the blind roller in a photographic shutter a
collar thereon having certain freedom of rotary motion, relatively to a pin fixed to
the axis, a spring lever with two latch studs, the one arranged to be engaged by
the pin, the other by a projection from the collar, substantially as and for the
purpose set forth.
- נ.י.ת
ABEL & IMRAY,
Agents for the Applicant.