Improvements in Shutters for Photographic Cameras.
Year: 1891

page_text: Date of Application, 14th Oct., 1891
Complete Specification Left. 13th July, 1892-Accepted, 27th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
We, JOHN EDWARD THORNTON, and EDGAR PICKARD, of Saint Mary's Street,
Deansgate, Manchester, in the County of Lancaster, Manufacturers, do hereby
declare the nature of this invention to be as follows:-
"
and is
This invention relates to what are known as "instantaneous shutters'
designed with the object of providing such a shutter of simple construction also of
providing such shutters with an additional auxiliary or safety blind which will
prevent light passing through whilst being set for exposure.
A box or frame with an aperture or a perforated back and front of ordinary con-
struction carries both the exposing and the safety blinds the former being mounted
to run over one or two smali rollers one at each end of the box and the latter
attached to a spring roller at one end thereof.
The expusing blind is a square or rectangular piece of suitable opaque material,
such as macintosh, cloth, leather, or the like, of a size to cover either the back or
front apertures. To one end of this opaque exposing blind, two cords chains or
strings are attached which pass over the top roller and down through the bottom of
the box terminating in a ring tassel or knob; to the other end of this blind are
attached or connected a spring or springs preferably two fine steel spiral springs
which pass under the bottom roller and are carried upwards to the top of the box.
Instead of these steel wire springs india rubber springs may be used or the blind
may be attached by means of cords or strings to the barrel of a coiled or volute
spring or to a spring roller. Where the fine spiral springs are used they may be
fastened to the top of the box or they may be connected to a cord or ring which can
be drawn up and hooked over pins in various positions to vary the tension of the
springs for the purpose of adjusting the speed of the shutter.
In the box between the top and bottom rollers we place a block or bar of wood
or metal either clear of the openings or with an aperture therein which corresponds
therewith. On the back of this block or bar is placed a bevelled projection over
which the blind slips and catches on the underneath edge when drawn down to cover
the apertures or close the shutter. A movable strip is hinged or pivoted between the
block and the blind by raising which the blind is lifted clear of the projecting catch
and released for exposure. The strip may be lifted or moved by a cord, push, or
pneumatic device of ordinary construction.
To the spring roller at the bottom of the box we attach one end of the safety
blind which is also of opaque material and of sufficient length when unwound to
cover the opening in the box. To the other end of the safety blind we attach cords,
chains, or strings which are passed over the top roller or through eyelets and down
through the bottom of the box where they connect with those attached to the other
blind.
This safety blind may also be used with the blinds of instantaneous or time
shutters such as are at present in use and it will also be obvious that the exposing
blind herein described may be used without the safety blind but at present we
prefer to use the two togethe".
In operation before exposure the exposing blind covers the front opening of the
shutter and the safety blind is wound upon the spring roller. To set the shutter or
adjust the blind for exposure the two sets of cords are pulled together by the tassel.
The two blinds are thus drawn forward at the same time the end of one overlapping
the end of the other forming as it were one continuous blind. The cords are
pulled until the exposing blind has passed from the back, over the top roller, to the
front, whereupon it catches under the projection and is held against the stress of the

page_text: driving spring. It then covers the front aperture, so as to effectually exclude all
light from passing through, and the safety blind, having served its purpose in
covering the aperture until the exposing blind was in position, immediately, when
the tassel is released, re-winds upon the spring roller. To make the exposure the
exposing blind is lifted clear of the projection by raising the hinged strip, and
immediately the exposing blind flies back to its normal position uncovering and
re-covering the aperture in its passage.
A shutter with safety blind such as described will be found especially suitable for
hand cameras though it will be useful for ordinary cameras.
Dated this 13th day of October 1891.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
We, JOHN EDWARD THORNTON, and EDGAR PICKARD, of Saint Mary's Street,
Deansgate, Manchester, in the County of Lancaster, Manufacturers, 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 :-
In blind shutters as at present constructed for photographic cameras by which
instantaneous exposures of the plates are obtained and instantaneous photographs
produced, no provision is made for preventing the exposure of the lens whilst the
blind of the shutter is being set or raised for the next picture and it has therefore
been necessary either to set the shutter before inserting the plate or to cap the lens
while the shutter was being set. This invention is designed with the object of
constructing a blind shutter which can be raised or set without exposing the lens
and of providing an instantaneous shutter of simple construction.
It consists essentially in constructing the shutter with two blinds-an exposing
blind and a safety blind-both of which will together travel across the lens when
the shutter is being set, to prevent light entering, and the auxiliary or safety blind
will return back as soon as the shutter is set and the exposing blind ready to be
released for the required exposure; and also in an exposing blind which travels
from the front to the back of the shutter over a loose roller at one end held and
drawn back by elongated springs and at the other end held and drawn forward by
cords which pass over the same rollers.
The invention will be fully described with reference to the accompanying
drawings:-
1
Fig. 1. Front elevation (with the cover removed) of instantaneous shutter
constructed according to this invention with auxiliary safety blind and improved
exposing blind.
Fig. 2. Transverse sectional elevation of same.
Fig. 3. Front elevation of modified form of shutter, the hood for the lens
projecting in front of shutter.
Fig. 4. Back elevation of same.
Fig. 5. Transverse sectional clevation of same.
Fig. 6. Transverse sectional elevation of same showing blinds drawn up.
Fig. 7. Transverse sectional elevation showing exposing blind set and safety
blind returned to its position.
Fig. 8. Transverse sectional elevation of shutter showing the safety blind in
conjunction with another form of exposing blind.
Fig. 9. Front elevation (front cover removed) showing shutter with exposing
blind without the safety blind.
Fig. 10. Transverse sectional elevation of Fig. 6.

page_text: In the frame or box A we place two blinds, an exposing blind B, and an auxiliary
or safety blind C. The exposing blind B is mounted to move from one side to
the other of the box A over a small roller D at the top end and the safety blind
is attached to a spring driven roller J at the other end thereof.
To the other
The auxiliary or safety blind C is formed of an opaque material such as black
macintosh, cloth, leather or the like of a sufficient length when unwound to extend
past or cover the aperture or openings a in the box A. It is attached by one
end to the spring roller J, by which it is wound up when released.
end of the safety blind we attach cords, chains or strings
the roller D' or over the roller D over which the safety blind also passes and down
through the bottom of the box where they connect with the cords attached to
the exposing blind B. By the cords c the safety blind C can be drawn up to the
position shown in Fig. 6.
which are passed over
is
The exposing blind B is preferably a square or rectangular piece of flexible
material, also opaque, of a size about equal to or sufficient to cover either the
back or front apertures a of the shutter. At one end the exposing blind B is
attached or connected to a spring or springs preferably two fine steel spiral
springs E which pass round pulleys F on the ends of the lower roller J or round
a separate roller and at the other side are carried upwards to the top of the
box A. The springs E are either fastened to the top of the box, or, as shown in
the drawing are connected to a cord e which passes through holes therein by drawing
up which the tension of the springs may be increased. The end of the cord
provided with a small ring or hook e which may when the cord is drawn up engage
with a small pin or hole e" on the top or in the front of the box. By this means
the tension of the springs can be varied for the purpose of adjusting the speed of
travel of the exposing blind B. To the top end of the exposing blind B, we
attach two cords which pass over the top roller D or D' and down through holes
in the bottom of the box terminating in a tassel, ring or knot, where they are
connected to the cords of the safety blind. To prevent the exposing blind B
covering the lens when focussing, or when desired to retain the lens uncovered or
exposed for any purpose the cords can be clamped by the cranked wire b¹ Figs. 1
and 2 or by a pin such as I¹ Figs. 3 and 4 which can be inserted into a hole "
provided in the front of the case A for the purpose.
In the box or case A between the top and bottom rollers we place a plate or
block G of metal, wood or other material. The plate or block G is formed with an
opening corresponding to the opening a in the case A at the front and back of the
shutters.
The exposing blind B is held in position when shut or closed by a bevelled
catch H over or against which the exposing blind B slides as it is drawn up and
upon the underneath side of which the edge of the blind B catches when drawn
down or set, to close the shutter or cover the apertures a prior to an exposure.
The catch H may be pivotted to the case A as in Fig. 2, and the blind released
by drawing it back by a small button h or the catch H may be fixed to the block G
as in Figs. 3-5 etcetera and the blind be released by a movable strip I hinged
to the face of the block between it and the blind which in being moved forward
presses the blind forward with it clear of the catch H. The strip I
be moved or lifted by a pneumatic bulb or by a button and cord attached
to it.
may
The safety blind C may be used with other forms of flexible exposing blinds at
present in use in instantaneous or time shutters, in Fig. 8 it is shown in conjunction
with a spring blind B which travels from the roller D' to the spring driven roller F
having an opening or aperture in the centre to give the exposure as it travels past
the lens.
The exposing blind B arranged as herein described may be used as shown in
Figs. 9 and 10 without the safety blind C, to form a cheap and simple instantaneous
shutter which can be easily constructed and will not be liable to get out of order.
When the shutter is in position on the camera, before exposure or being set to

page_text: give an exposure the exposing blind B covers the front aperture a of the shutter
and the safety blind C is wound upon the spring roller J. To set the shutter or
adjust the blind B for exposure the two blinds are drawn forward at the same time
by pulling the two sets of cords by the button or tassel. The edge of the safety
blind Coverlaps the edge of the blind B, forming as it were one continuous blind,
the junction of the two being light-proof so that as the edge of the blind B or an
aperture in it passes over the lens, no exposure is made or light admitted. The
cords and care pulled until the exposing blind B has passed from the back of
the shutter over the top roller D, to the position shown in the front Fig. 6, where-
upon it catches under the projection H and is thereby held against the pull of the
springs E. In this position the blind B covers the front aperture a so as to
effectually exclude all light from passing through, and the safety blind C, having
served its purpose in covering the aperture until the exposing blind was in position,
immediately, when the tassel is released, re-winds upon the spring roller J, returning
to its normal position Fig. 7. To make the exposure the exposing blind is lifted-
clear of the projection H by the cord or by raising the hinged strip I either
by the pneumatic bulb or the button, and immediately the exposing blind
flies back to its normal position uncovering and recovering the aperture a in its
passage.
Where the safety blind is not used as in Figs. 9 and 10 the description so far
as it relates to the exposing blind B will be precisely the same. And where
the safety blind C is used with other forms of exposing blinds as in Fig. 8, it
is drawn forward with the exposing blind as already described by the cord e and
returned to its normal position as soon as the blind B is secured and the cord
released.
A shutter with safety blind such as described will be found especially suitable
for hand cameras though it will be useful for ordinary cameras.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
1. A shutter for photographic cameras constructed with two flexible travelling
blinds, one an exposing blind to open and close the lens or give an exposure when
released, and the other an auxiliary safety blind to travel with and cover the edge
or aperture of the exposing blind when it is being set to prevent light entering and
then return to its normal position.
2. A shutter for photographic cameras constructed with a flexible opaque
exposing blind which travels from the front to the back of the shutter over a small
roller to the corners of which are attached at one edge elongated springs by
which it is held and drawn back, and at the other edge cords by which it is drawn
forward, substantially as described.
3. A shutter for photographic cameras having an exposing blind which travels
from back to front of the shutter, actuated by elongated springs attached to the
arms at one edge and held in position when set, by a projecting catch with which
one edge of the blind engages, and an auxiliary safety blind mounted on a spring
roller which is drawn forward across the lens with the exposing blind and wher
released returns to its normal position substantially as and for the purpose
described.
4. A shutter for photographic cameras constructed substantially as described and
shown with reference to either of the figs. of the drawings.
11 101
T.... 1900
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.