Improvements in Lens Shutters and Camera Fronts.
Year: 1886

page_text: Date of Application, 27th Sept., 1886.
Complete Left, 27th June, 1887.
Complete Accepted, 29th July, 1887,
PROVISIONAL SPECIFICATION.
Improvements in Lens Shutters and Camera Fronts.
I, JOHN EDWARD THORNTON, of 3, New Lorne Street, Moss Side, Manchester,
in the County of Lancaster, Printer, do hereby declare the nature of this invention
to be as follows:-
The improvements which are the subject of this invention are threefold, and are
hereinafter more definitely described, and have for their object: Firstly :-The con-
struction of a lens shutter which can be made to operate and admit light through the
lens to the sensitive plate in a photographic camera, either instantaneously or for a
lengthened period; and, Secondly:-To provide means to show or indicate outside
whether the shutter is open or closed; and, Thirdly :-To reduce the number of loose
parts and also the bulk, by placing the shutter so as to work inside the camera front,
and behind the lens. In this case the shutter is always attached to the camera ready
for use, and the usual cap may be used for exposing instead of the shutter, if
desired, without detatching the said shutter, from the camera.
In constructing a Lens Shutter according to my invention, I form a box-shaped
casing (hereinafter called the case), which may be made to fit on the hood of lens, as
usual, or may be made to form part of the camera front (as hereinafter described), and
having an aperture through the same for the passage of light. In the said case I
insert two rollers, working in suitable end bearings. One of the said rollers contains
a spiral spring, and is hereinafter called the spring roller; this roller is provided at
one end with a one-toothed rachet, and a spring catch to engage with the same, for
the purpose of allowing extra tension to be put on roller, when required, so as to cause
the shutter to work quicker. The other roller (hereinafter called the winding roller)
is provided at one end with a rachet and pawl, or catch, to prevent a reverse action
of the said roller. A flexible blind, of material impervious to light, and having a
suitable-sized aperture therein, to allow the passage of light, is attached by its two

page_text: ends to the two rollers, so as to admit of being wound from off one roller on to the
other.
When the blind is wound from off the spring roller on to the winding roller, it
causes the spiral spring to coil itself tighter, and so put tension on the blind. When
the pawl is thrown out of gear with the rachet, the blind, being released, winds itself
back again on to the spring roller, and the aperture in blind allows light to pass
through, whilst it is passing across the lens.
In carrying out the first part of my invention, I place on one end of the winding
roller, to which the rachet is attached, a small pinion, which is made to gear into a
toothed wheel, which I call the detent wheel; the number of teeth on this wheel are
so calculated that when the blind has partly wound on to the spring roller, and the
aperture in the said blind has come opposite the lens, and the shutter is open, the said
wheel shall have gone through one complete revolution.
Near the periphery of this said wheel a small stud or stop is fixed.
A lever, for the purpose of actuating the release, is pivoted to the side of case, and
a small detent or stop is pivoted to this lever in such a manner that when the said
detent is turned down it will come in the plane of the stud on detent wheel, and
thereby arrest the motion of the said wheel after one revolution; and when turned
over in the other direction it will be out of the plane of the stud, and so allow the free
revolution of the said wheel. A spring, pressing against the lever, keeps it out of
contact with the detent wheel, until desired.
To set the shutter for an exposure, the blind is wound on to the winding roller, and
the pawl is put into gear with the rachet to prevent its unwinding. If it is desired
to give an exposure of short duration (commonly called instantaneous), the detent is
turned over out of the way of the stud. The detent lever is so pivoted, that, when
pressed, the other end lifts up and throws the pawl out of gear with the rachet on
winding roller. The blind, thus released, instantly winds itself on to the spring
roller, allowing the passage of light through the lens during the passage of the
aperture in blind, and again closes the lens. If it be desired to give an exposure of
longer duration, the detent catch is turned over towards the detent wheel. When the
lever is pressed down, the detent is caused to come in the plane of the stud, and the
pawl is thrown out of gear, thus releasing the blind, and causing the detent wheel to
revolve. After one revolution of the said wheel, the detent catches against the stud,
and so prevents the wheel from revolving any further, thus causing the shutter to
remain open as long as the detent lever is pressed down. When the pressure is
released, the spring, pressing against the said lever causes it to rise, and allow a
further revolution of the detent wheel, thus allowing the shutter to close. A stop
spring operates against the pawl, to prevent it falling into gear with the rachet
during a lengthened exposure, or any other suitable device may be used.
The usual punematic cylinder, piston, and ball, may be attached, if desired, for the
purpose of actuating the detent lever, in such a manner that the shutter will remain
open as long as the ball is pressed, and close when the pressure is released.
In carrying out the second part of this invention, I attach a pinion to the detent-
wheel axle, so as to revolve therewith; a toothed wheel is made to gear into this
pinion, and the number of teeth are calculated so that this wheel shall make one
revolution while the blind winds completely off one roller on to the other.
A pointer, or index finger, is attached to this wheel, and indicates, on a dial or
plate, whether the shutter is open or closed. By turning this wheel backward, through
one revolution, the blind may be wound on to the winding roller more readily than
by several turns of the said roller.
A brake, for regulating the speed, may be caused to operate against the indicating
wheel, and may be adjusted by a screw, spring, or other suitable device.
In carrying out the third part of this invention, I construct a camera front in the
form of a shallow box or case, with an aperture through the same, and I place the
shutter inside the said case, so as to work behind the lens. To the back portion of
this case the bellows are attached, and to the front portion the lens may be attached
in the usual way, or the ordinary lens panel inserted.

page_text: By inserting the shutter in a camera front as described, the whole is more
compact than when the shutter is in a separate case, and it does not interfere with
the free use of the various parts of the camera.
In order not to unduly increase the thickness and bulk of the camera front, and
still make room for the rollers to work free, I make openings in the case to allow
the rollers to partly project, and I cover the projecting parts each with a half tube,
or box-shaped covering, to make the whole light tight; or the case may be thicker,
if preferred, and the rollers placed entirely inside. The case may be made of wood,
metal, or other suitable material, either wholly or in part combination.
I do not bind myself to any particular position of the parts, and the rollers may be
placed in any convenient position, either horizontally or vertically.
Dated this 24th day of September 1886.

page_text: Improvements in Lens Shutters and Camera Fronts.
I, JOHN EDWARD THORNTON of 3 New Lorne Street, Moss Side, Manchester in
the county of Lancaster Printer 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 :—
as
The improvements which are the subject of this invention consist in the
construction of a lens shutter for use in a photographic camera formed so
to operate and admit light through the lens to the sensitive plate either instan-
taneously or for a lengthened period: to indicate externally whether said shutter
is open or closed; and to reduce the number of loose parts and also the bulk
by placing said shutter in a position so as to be within the camera front, or form part
thereof, and to work behind the lens. In the latter case, the shutter is always
attached to the. camera ready for use, and the usual cap may if preferred be employed
for exposing instead of the shutter, without detaching said shutter from camera.
In order more clearly to describe my invention I have annexed hereunto a sheet of
drawings In the several views illustrated therein similar letters refer to similar
parts: Figs. 1 and 2 are side views and Fig. 3 front view of a photographic spring
blind or shutter: In Fig. 1. the shutter is represented closed and in Fig. 2 the shutter
is open..
:
In the construction of a lens shutter according to this invention I form a case or
box a in which are contained two rollers 6 and 6' with spring blind c attached of the
description ordinarily used in an instantaneous shutter, and having the usual aperture
or opening in said blind for the passage of light: I place on one end of the winding
roller a small pinion d which gears into a toothed wheel e which I term a detent
wheel the number of teeth on this detent wheel are calculated so that when the
blinde has partly wound on the spring roller & the aperture in said blind has come
opposite the lens and the shutter is open, the detent wheel e shall have gone through
one revolution: the detent wheel e is formed with a stud or stop near the periphery
of said wheel for the purpose of actuating the release of blind c, a lever g is
pivotted to side of shutter case a to this lever g, a detent or stop is pivotted
in such a manner that when said detent his turned down it will come in the
plane of stud f on detent wheel e and thereby arrest the motion of said wheel e
after one revolution, and when turned over in the opposite direction it will be out
of the plane or path of stud f and so allow the free revolution of the detent wheel e :
The lever g actuates a pawlj placed over rachet d which is on shaft of and behind the
pinion d' On winding the roller b, this pawl is kept out of contact with ratchet d
when not required by means of spring k. To set the shutter for an exposure the blind is
wound on to the winding roller 6 the pawl j being first put into gear to prevent the
blind unwinding: If it is desired to give an exposure of short duration, commonly
called instantaneous, the detent his turned over out of the way of stud f, as repre-
sented in dotted lines on drawing: the detent lever g is pivotted at g' and when the
end is pressed outwards the end g³ is lifted and throws the pawl out of gear with
the pinion d on winding roller b: the blind c being thus released instantly winds itself

page_text: on to the spring roller b' allowing the passage of light through the lens during the
passage of aperture in blind, and again closes the lens: If it is desired to give an
exposure of longer duration the detent catch h is turned over towards the detent
wheel e: when the lever g is pressed outwards the detent his caused to come in the
path of the stud f and the pawlj is thrown out of gear, thus releasing the blind and
causing the detent wheel to revolve: After one revolution of the said wheel e the
detenth catches against the stud f and thus prevents the wheel from revolving any
further by these means the shutter is caused to remain open so long as the detent
lever y is pressed outwards: When pressure is released the detent wheel will revolve
further and thus allow the shutter to close : Pressure on the lever g is obtained by
pneumatic bag 1, or other suitable means. Figs. 4 and 5 show a modified form of
lever g in combination with detent, detent wheel, pawl and other parts as herein
above described in Fig. 4 the shutter is represented open and in Fig. 5 the shutter
is closed.
Fig. 6. on drawing represents the second part of this invention: I attach a pinion m
to the detent wheel axle so as to revolve therewith: a toothed wheel n is made to
gear into this pinion and the number of teeth are calculated so that this wheel shall
make one revolution while the blind winds completely off one roller on to the other :
A point or index finger is attached to the wheel 'n and indicates whether the shutter is
open or closed.
By turning this wheel backward through one revolution the blind may be wound.
on to the winding roller more readily than by several turns of the said roller. Fig. 7.
illustrates the third part of this invention: in this view the camera front is represented
in the form of a thin box or case a, with an aperture for the passage of light: I place
the flexible blind or shutter c within this case so as to work behind the lens. To the
back portion of this case the bellows o are attached, and to the front portion the lens
may be attached in the usual way, or the ordinary lens panel inserted.
In order not to unduly increase the thickness of the camera front, and yet provide
room for the rollers to work free I make openings in the case to allow the rollers to
partly project: I cover these openings and projecting parts with a half tube or box
shaped covering p to make the whole light tight or if preferred the case a forming
front board may be thicker and the shutter made complete and entire placed inside
between front and back of said board: I make the case either of wood, metal, or
other suitable material entirely, or in part combination.
I do not confine myself to any particular position of the parts herein above described,
and the rollers may be placed either horizontally or vertically.
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
1st. In combination with a photographic spring blind or shutter, the employment
of a detent and detent wheel marked e and h on accompanying drawing, for the
purpose herein before described.
2nd. In combination with a photographic spring blind or shutter either of the
ordinary description or other preferred form, the employment of a dial or indicator
marked n' on accompanying drawing, for the purpose and in the manner herein before
described.
3rd. In a photographic camera the combination of the front board with a
photographic shutter inserted therein, and forming either a part thereof or a
detachable shutter within said front board.
1000
JOHN EDWARD THORNTON,
Applicant.