Improvements in Roller Blind Shutters for Photographic Purposes.
Year: 1898

page_text: Date of Application, 21st Oct., 1898
Complete Specification Left, 21st July, 1899-Accepted, 26th Aug., 1899
PROVISIONAL SPECIFICATION.
Improvements in Roller Blind Shutters for Photographic Purposes.
SAMUEL DUNSEITH MCKELLEN, of 4, Bull's Head Yard, Manchester, Photo-
graphic Engineer, and JoHN DUNSEITH MCKELLEN, of 4, Bull's Head Yard,
Manchester, Manufacturer, do hereby declare the nature of this invention to be
as follows:-
Our invention relates to improvements upon the roller blind type of photo-
graphic shutter, such as those known as the Kershaw, Thornton-Pickard, Swift
and others. The first part of our invention relates to an improved method of
giving prolonged exposures. Hitherto, in shutters of the type above named
there has been and is now a revolving wheel with certain projections. The first
projection is a pin or stud. When the shutter is wound up this pin or stud rests
against a moveable lever. When the lever is lifted up high enough the pin passes
under it, and the wheel revolves its full distance, allowing the blind to return to
its normal position, carrying the aperture across the lens and thus completing the
exposure. This is called the instantaneous action. The second projection is
a stud placed in such a position that when the cord is drawn halfway out, and
the aperture in the blind is opposite to, and uncovers, the lens the said stud
will rest against the before-mentioned lever and prevent the blind returning
until the lever is sufficiently raised to allow it to pass under, when the blind will
run back to its original position, covering the lens. The third projection is a
hook mounted on the wheel a little nearer the centre so that the lever, being
moved a given distance, when raised above the first named pin or stud shall
present itself in front of the hook thereby stopping the revolution of the wheel
and causing the aperture of the roller blind to stand in front of the lens, giving
a prolonged exposure. When the lever is allowed to return to its normal position
the aforesaid hook passes over it, and the wheel revolves until the shutter is
closed. This has been called the time exposure.
These three movements constitute what is commonly called the roller blind
shutter as at present on the market. Now, our invention is designed to supply
an additional movement together with the three movements already named. For
this purpose we provide another stud fixed in a position behind the hook pre-
viously named, and a little nearer the centre of the wheel, so that a further move-
ment of the lever places it in such a position that when the said hook passes
over it as in the previous case the wheel will only revolve until the stud reaches
the lever where it will rest. The aperture in the blind having then arrived
opposite to the lens the desired exposure goes on until the lever is again lifted
above the said pin when the wheel will resume its revolution, thus
completing the exposure as before.
of
The advantage of this extra movement is that a prolonged exposure any dura-
tion may be given without the necessity of holding the releasing cord, or the
tube and bulb, in the hand the whole of the time the exposure is continued.
The second part of our invention is for a more ready way of attaching the

page_text: roller blind shutter to the camera front when used as what is called a behind-
lens shutter. In such a case the usual method hitherto employed has been by
means of screws passing through the back of the shutter and so fastening it to the
camera front. By our method we make a pair of plates on either side of the
shutter project enough behind to allow a pair of bayonet joints to be made in
them. These are intended to catch on to pins in the side of the front board
which is shaped to admit of the said pins being placed in correct position. The
shutter can by this means be easily removed from or replaced in the camera
without the necessity of unscrewing and without the use of any kind of tool.
If the shutter is not to be used attached to the camera front but as a separate
article the projecting plates may be left off, and the back of the shutter finished
in the same way as the front hereafter described. We form the body, viz. the
two sides and two ends, of aluminium or other convenient material. We make
a wood front to fit into the front of the aluminium frame and we fasten it to the
frame by any convenient method which will hold it firmly and in such a way
that the front shall be easily removed from the frame for any purpose such as
fixing a lens flange thereon, or for obtaining access to the internal parts of the
shutter, &c. The back may be attached in the same way or in some cases, such
as when used as a hand camera shutter it may be left off altogether; the front
board of the camera in that case may form the back of the shutter.
1000
S. D. McKELLEN.
J. D. McKELLEN,
Improvements in Roller Blind Shutters for Photographic Purposes.
We, SAMUEL DUNSEITII MCKELLEN, of Mill Street, Long Millgate, Manchester,
late of 4, Bull's Head Yard, Manchester, Photographic Engineer, and Joun
DUNSEITH MCKELLEN of Mill Street, Long Millgate, Manchester, late of 4, Bull's
Head Yard, Manchester, Manufacturer, 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:-
Our invention relates to improvements upon the roller blind type of photo-
graphic shutter, such as those known as the Kershaw, Thornton-Pickard, Swift
and others. The first part of our invention relates to an improved method of
giving prolonged exposures. Hitherto, in shutters of the type above named
there has been and is now a revolving wheel with certain projections. The first
projection is a pin or stud. When the shutter is wound up this pin or stud rests
against a moveable lever. When the lever is lifted up high enough the pin passes
under it, and the wheel revolves its full distance, allowing the blind to return to
its normal position, carrying the aperture across the lens and thus completing the
exposure. This is called the instantaneous action. The second projection is
a stud placed in such a position that when the cord is drawn halfway out and
the aperture in the blind is opposite to, and uncovers the lens, the said stud
will rest against the before-mentioned lever and prevent the blind returning.
until the lever is sufficiently raised to allow it to pass under, when the blind will
run back to its original position, covering the lens. The third projection is a
hook mounted on the wheel a little nearer the centre so that the lever, being
moved a given distance, when raised above the first named pin or stud shall
present itself in front of the hook, thereby stopping the revolution of the wheel

page_text: as
and causing the aperture of the roller blind to stand in front of the lens, giving
a prolonged exposure. When the lever is allowed to return to its normal position.
the aforesaid hook passes over it and the wheel revolves until the shutter is
closed. This has been called the time exposure. These three move-
ments constitute what is commonly called the roller blind shutter
at present on the market. Now our invention is designed to supply
For
an additional movement together with the three movements already named.
this purpose we provide another stud fixed in a position behind the hook pre-
viously named and a little nearer the centre of the wheel so that a further move-
ment of the lever places it in such a position that when the said hook passes
over it as in the previous case the wheel will only revolve until the stud reaches
the lever, where it will rest. The aperture of the blind having then arrived
opposite the lens the desired exposure goes on until the lever is again lifted,
above the said stud when the wheel will resume its revolution thus
completing the exposure as before. The advantage of this extra movement is that
a prolonged exposure of any duration may be given without the necessity of
holding the releasing cord, or the tube and bulb, in the hand the whole of the
time the exposure is continued.
The second part of our invention is for a more ready way of attaching the
roller blind shutter to the camera front when used as what is called a behind
lens shutter. In such a case the usual method hitherto employed has been by
means of screws passing through the back of the shutter and so fastening it to the
camera front. By our method we make a pair of plates on either side of the
shutter project enough behind to allow a pair of bayonet joints to be made in
them. These are intended to catch on to pins in the side of the front board
The
which is shaped to admit of the said pins being placed in correct position.
shutter can, by this means, be easily removed from, or replaced in, the camera
without the necessity of unscrewing and without the use of any kind of tool.
If the shutter is not to be used attached to the camera front but as a separate
article the projecting plates may be left off and the back of the shutter finished
in the same way as the front hereafter described. We form the body, viz.: the
two sides and two ends, of aluminium or other convenient material. We make
a wood front to fit into the front of the aluminium frame and we fasten it to the
frame by any convenient method which will hold it firmly and in such a way
that the front shall be easily removed from the frame for any purpose such as
fixing a lens flange or for obtaining access to the internal parts of the shutter,
or other required purposes.
The back may be attached in the same way or in some cases such as when used
as a hand camera shutter it may be left off altogether; the front board of the
camera in that case may form the back of the shutter.
In order that our invention may be more clearly understood we append drawings
of the same.
Figs. 1 and 2 are respectively side and front elevations of a roller blind shutter
to which our invention applies. Figs. 3, 4, and 5 are detailed views of the revolv-
ing wheel and lever shown in Fig. 1. Fig. 1 is a detailed view of the spring, c,
which holds down the lever, b, and Figs. 1, 1°, and 1ª are sectional plan views
on the lines A A, B B, and C C respectively in Fig. 1.
is the revolving wheel, and a² and a² are respectively the 1st and 2nd pro-
jecting pins or studs on it. a³ is the projecting hook, and a' is the additional
projecting stud provided to get the further movement as described. b is the
moveable lever pivotted at 6 and having a projecting edge & formed upon it
to engage with the projections on the revolving wheel a. c is the spring which
engages with the end of 6 and ensures it returning to its normal position when
the rubber teat dis deflated. c, c², and are notches cut in the end of the
spring which ensure the proper sideways movement being given to the moveable
lever for its edge to engage with the projections a, a, ³, or a as desired.
In Fig. 1 the arrow shows the direction in which the wheel a will revolve when

page_text: the shutter is being set for exposure by drawing down the corde by means of the
tassel e¹. In Figs. 3, 4, and 5 the arrows show the direction in which the wheel a
will revolve when the exposure is made by inflation of the teat d, thus lifting
the lever high enough to allow the pin a to pass under it.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. In a photographic roller blind shutter a combination of movements for the
Eurpose of obtaining instantaneous, short time, and prolonged time exposures,
as described.
2. In a photographic roller blind shutter the use of projecting sides in which
may be formed a bayonet joint device for more convenient attachment to a camera
front, as described."
S. D. MCKELLEN.
J. D. McKELLEN.