An Improved Photographic Shutter.
Year: 1898

page_text: Date of Application, 25th Mar., 1898
PROVISIONAL SPECIFICATION.
An Improved Photographic Shutter.
We, SAMUEL DUNSEITH MCKELLEN, of 34, Claude Street, Crumpsall, Man-
chester, Manager, and JOHN DUNSEITH MCKELLEN, of 4, Bull's Head Yard,
Manchester, Camera Manufacturer, do hereby declare the nature of this inven-
tion to be as follows:
Our invention is for a photographic shutter more especially to be used in hand
cameras but which may be made to be used with stand cameras either fitted on
It consists of a revolving
the front of the lens or working behind the same.
disc which is made to revolve in front of or behind the lens and the invention
which we have worked out is for a novel means of causing the revolution of the
said disc at the right time and through the proper distance. For this purpose
we fit a wheel with certain shaped teeth or indents on the middle of the said
disc and attached to it so that the wheel and disc must revolve simultaneously
clear of the disc. We provide a lever swivelled at its outer end and having
on the other a pawl of peculiar make. To the free end of the lever we attach
one end of a spiral spring, the other end of the spring being fixed to a stud placed
in such a position that the free end of the lever with the pawl is always being
pulled towards the centre of the disc. When the lever is pulled from the centre
of the disc tension is put on the spiral spring and the pawl is at the same time
caused to engage on the indents of the centre wheel so that if the disc were
free to revolve the pawl attached to the lever being drawn by the spring would
cause it to do so. Suitable means are adopted to hold the disc with its opaque
part in front of the lens and when desired to make an exposure means are
arranged to release it and allow it to revolve the proper distance to give exposure
and stop again at the proper place.
We, SAMUEL DUNSEITH MCKELLEN, late of 34, Claude Street, Crumpsall, Man-
chester, now of 66, Lansdowne Road, Crumpsall, Manchester Manager, and
JOHN DUNSEITH MCKELLEN, of 4, Bull's Head Yard, Manchester, Camera Manu-
facturer, 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 is for a photographic shutter more especially to be used in hand

page_text: cameras but which may be made to be used with stand cameras either fitted on
the front of the lens or working behind the same. It consists of a revolving
disc which is made to revolve in front of or behind the lens and the invention
which we have worked out is for a novel means of causing the revolution of the
said disc at the right time and through the proper distance. For this purpose
we fit a wheel with certain shaped teeth or indents on the middle of the said
disc and attached to it so that the wheel and disc must revolve simultaneously.
Clear of the disc we provide a lever swivelled at its outer end and having
on the other a pawl of peculiar make. To the free end of the lever we attach
one end of a spiral spring, the other end of the spring being fixed to a stud placed
in such a position that the free end of the lever with the pawl is always being
pulled towards the centre of the disc. When the lever is pulled from the centre
of the disc tension is put on the spiral spring and the pawl is at the same time
caused to engage on the indents of the centre wheel so that if the disc were
free to revolve the pawl attached to the lever being drawn by the spring would
cause it to do so. Suitable means are adopted to hold the disc with its opaque
part in front of the lens and when desired to make an exposure means are
arranged to release it and allow it to revolve the proper distance to give exposure
and stop again at the proper place.
In order that our invention may be more clearly understood we append draw-
ings of the form of the same which we find most convenient to adopt.
Fig. 1 is an elevation.
Fig. 2 is a plan view of Fig. 1.
Fig. 3 is a view similar to Fig. 1, but with the various parts set ready for being
released and also shows in dotted lines a midway position in order to explain
more clearly the action of the double pawl.
Fig. 4, is a detached view of the double pawl hereafter more particularly
referred to.
c is
bb is the revolving disc referred to, which is here shown mounted upon a
bed plate, a, but which may be mounted direct on the wood of the camera.
a lever which presses upon the disc ¹ and holds it with its opaque part cover-
ing the aperture. d is a button so arranged that, when pressure is applied to
it the lever c is raised up from the disc b¹ and allows it to revolve freely. g is
a shouldered screw upon the shoulder of which is swivelled the lever h clear of
the disc bbi is the pawl of peculiar make attached to the outer end of the
lever h. In these drawings a double toothed pawl is shown but when a revolving
disc with three or more wings is used a single toothed pawl only is necessary.
f is the wheel with teeth or indents and mounted on the disc bbi.
The form previously described is what we consider the best method of working
out the invention, but, if preferred, pins attached to the middle part of the
revolving disc may be substituted for the before named wheel: the pawl acting
upon the pin in the same manner as upon the indented wheel.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed we declare that what
we claim is :-
1. The application of the force produced by a spring acting on a lever in the
manner described applied near the centre of the revolving disc to cause it to
revolve for the purpose already indicated.
Tatad this 93rd day of Documber 180S