Improvements in and relating to Shutters for Photographic Cameras.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Shutters for Photographic
Cameras.
I, HENRY BAKER NORTON, a Citizen of the United States of America, residing
at 42 Third Street South, in the City of Minneapolis, County of Hennepin and
State of Minnesota, one of the United States of America, Photographer,
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 :-
This invention relates to certain new and useful improvements in instantaneous
shutters for photographic cameras; and it has for its object to provide a shutter of
the character mentioned, the construction and operation of which will serve to so
distribute the light as to give upon the dark objects in the foreground, more light
than is given to the background of the picture.
The shutter is intended more especially for use in out-of-door or landscape
photography, in which the background of the picture is frequently of either the
clear sky or of clouds, and it is well known in photography that in order to secure
the best results in pictures of this kind, the background of the picture should be
given a much shorter exposure than is required by the darker objects in the fore-
ground and the essential object of the present invention is to provide a means
whereby the background may be protected from over-exposure, and to so distribute
the light as to fully time the foreground of the landscape and at the same time
prevent the sky from being overtimed by too much light."
To these ends and to such others as the invention may pertain, the same consists
in the peculiar construction, and in the novel combination, arrangement, and adap
tation of parts, all as more fully hereinafter described, shown in the accompanying
drawing, and then specifically defined in the appended claims.
The invention is clearly illustrated in the accompanying drawings, which, with
the letters of reference marked thereon, form a part of this Specification, like letters
of reference indicating like parts throughout the several views, and in which
drawings-
Figure 1 is a front view of a camera-shutter constructed in accordance with my
invention.
Figure 2 is a rear view of the same.
Figure 3 is a rear view of the shutter with the back plate removed.
Figures 4, 5, and 6, are details which will be more fully hereinafter described.
Reference now being had to the details of the drawings by letter, A, represents
the rear plate of the shutter, which is provided with the usual opening A', and rear-
wardly extending flange or collar, A, which serves to permit the shutter to be
attached to the camera, and upon its opposite side the said plate is provided with a
peripheral flange, A, said flange being screw-threaded upon its inner side, as shown
at, a, to receive the screw-threaded extension or peripheral flange, B', upon the
front plate, B. The disk, C, which is preferably constructed of sheet metal and of

page_text: substantially the form shown, is loosely sleeved upon the central pivot of post, A',
upon the inner face of the plate, A, and upon the enlarged base portion, A', of said
post is coiled the spring, D, one end of which spring is attached to the post and its
opposite end secured to a post or projection, D', upon the rear face of the disk, C,
as shown. The disk is provided at one side of its pivotal centre with a substantially
pear-shaped opening, CT, for a purpose which will presently appear.
E, is a flat strip of spring metal which is riveted or otherwise suitably secured
to the inner face of the rear plate, A. In the present instance I have shown this
plate secured by rivets, a', at one end of the plate, and by a screw, a', at a point
substantially one-half of the distance between the longitudinal centre of the spring-
plate and its free end, and the said free end, E', is inclined outwardly from the
plate, A, and is provided with a lug or catch, E', which is adapted when the
disk, C, is rotated, as hereinafter described, to enter the opening b, in the disk and
hold the same against the tension of the coiled spring, D.
Within a suitable opening, F, provided in the plate, A, directly beneath the
longitudinal centre of the spring-plate, E, is loosely seated the plug, F' and
surrounding this aperture upon the rear face of the plate, A, is a metallic
collar, F, to which the usual rubber pipe, F, with its accompanying air-bulb, F,
may be attached when it is designed to operate the shutter by the action of com-
pressed air. It will be seen that when the plug, F, is pressed inwardly its action
upon the rear face of the spring-plate, E, will serve to release the lug or catch, E',
from its engagement with the disk, C, when the said disk will be caused to rotate
by the tension of the spring, D, the throw of the disk being limited by the engage-
ment of the projection, C³, upon the disk with the stop, G.
H, is an irregular heart-shaped shield or disk of sheet-metal, one of the lobes, H¹,
being preferably larger than the opposite lobe, H. This shield is provided with a
pear-shaped opening, H', the smaller end of the opening being adjacent to the inner
end of the cut-away portion or indentation, H', upon the lower edge of the shield,
said aperture, H', being adapted to be fitted over the post, A', and to occupy the
space between the disk, C, and the front plate, B.
The front plate, B, of the device is provided with an opening, B³, corresponding
with the opening A', in the rear plate, A. Directly above the opening, B³, in the
plate, B, a semi-circular slot or opening, B, is provided in the plate, and through
this slot is passed a set-screw, 13, said screw passing through the opening, H*, in
the shield or disk, H, and into a screw-threaded opening provided for the purpose
in the disk, C. The set-screw, B', is provided with a shoulder, c, which is adapted
to bear upon the upper face of the washer, B', which is interposed between the
shield, H, and the plate, B, and thus the shield and disk are held together by
frictional contact. A screw, I, passed centrally through the plate, B, passes into
the central post, A', and serves to retain the plate in position, while the post serves
as a pivotal centre upon which the disk, C, and shield, or disk H, rotate, as will be
readily understood. It will be observed upon reference to the drawings that the
disk, C, is bent so as to present a bearing-surface, d, upon the plate, B. By this
construction I am enabled to readily adjust the screw, B, so as to regulate the
speed of the rotating disk, as by tightening the screw the friction will be increased
and the speed lessened.
In operation the screw, B', is slightly loosened and the shield, H, is moved
either up or down, as may be required to properly regulate the exposure in the
picture to be taken. It will be readily seen that the proper adjustment of this
shield will require the exercise of judgment upon the part of the operator, and
that it will depend in each instance upon the nature of the background to be
included in the picture. Hence, if the background is very light while the objects
in the foreground are dark, the shield will of course be lowered, while if the
background should be dark the shield would be raised.
When it is considered that were the lobes, H', and H' similar in size and
form lines would be apt to be formed in the picture, my object in varying the
form and size of this portion of the shield will be understood, as by this con-

page_text: f
struction I am enabled to obviate this difficulty, and while I do not in this
commation de
the particular form of disk or shield shown,
I deem it an essential feature of invention that irregular forms and lengths
should be employed, in order to prevent the formation of lines upon the picture.
While I have shown the shutter a provided with the usual rubber pipe and bulb,
and prefer to operate the shutter by the use of compressed air, it is at once evident
that if for any reason it should be considered desirable the pipe and bulb may be
omitted and the shutter operated by hand.
It will be seen that by moving the screw, B' from left to right within the slot, B³,
the shutter-disk C, will be given a one-half revolution, and that it will be locked in
place by the engagement of the lug or latch upon the spring-plate, E, with the
aperture in the disk. By pressing the plug, F, the latch is disengaged, and the
tension of the spring, D, will serve to give the disk a one-half revolution, thereby
uncovering and again covering the lens.
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 :-
1. In a shutter for photographic cameras, the combination, with the sbutter
proper and mechanism for operating the same, of mechanism for regulating the
admission of light so as to allow a longer time exposure to the lower than to the
upper portion of the lens, and the disk having lobes of irregular and different forms,
substantially as and for the purpose specified.
2. In a shutter for photographic cameras, mechanism, substantially as described,
embodying an eccentrically-arranged supplemental shutter for regulating the width
of the lens opening upon a line corresponding with the axis of the shutter, substan-
tially as shown and described, and for the purposes set forth.
3. In a shutter for photographic cameras, the combination, with the shutter
proper, of an eccentrically-arranged supplemental shutter carried by the shutter
proper and adapted to be adjusted thereon to limit the width of the lens-opening
upon a line corresponding with the axis of the shutter, substantially as described.
4. The combination with the front and rear plates, A, and B, provided with
openings as described, the disk, C, pivoted between said plates and provided with
spring-actuating mechanism, and devices for releasing and regulating the movement
of the disk, of an irregular heart-shaped shield carried by the disk and adapted to
be adjusted thereon to regulate the vertical width of the lens-opening, substantially
as and for the purpose specified.
5. In a shutter for photographic cameras, the combination, with the shutter
proper and its actuating and releasing mechanism, of an irregular shield or plate
adapted to regulate the size and form of the lens-opening and prevent the formation
of lines upon the face of the negative, substantially as described.
6. In a photographic-camera shutter, the combination with the front and rear
plates, the rotatable shutter interposed between the plates, and the irregular shield
or plate, of mechanism, substantially as specified, for regulating the speed of the
shutter, substantially as and for the purpose specified.
Dated this 18th day of Anvil 1801
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.