Improvements in Photographic Cameras.
Year: 1888

page_text: Date of Application, 27th Oct., 1888
Complete Specification Left, 27th July, 1889-Accepted, 7th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Photographic Cameras.
We SAMUEL DUNSEITH MCKELLEN Photographic Engineer 3 Chapman Street
Hulme Manchester and JOHN DUNSEITH MCKELLEN Photographic apparatus maker
3 Chapman Street Hulme Manchester do hereby declare the nature of this invention
to be as follows:-
Our invention is for improvements in detective & other cameras and is intended
to provide in a cheap form an instrument which will serve the purpose of those who
are unable or unwilling to pay the high prices demanded for the more elaborate
instruments.
The camera consists of a front which in itself forms a shutter of peculiar & novel
construction which is hereinafter described. The camera body in the cheaper form is
a rectangular box but may be made with bellows if desired. At the back of the box
the plate holder (carrying as many plates as may be desired) is hinged it is of the same
sectional form as the camera and when hinged to it and closed the whole appears as
one continuous box the size being according to the size of the plates which are to be
used. At the back of the plate holder and forming the back end of the camera a lid is
hinged, strong springs are fixed on the inner surface of this lid so that when the plates
are in the holder & the lid & holder closed up the plates will be pressed home.
The front one being in proper register & bearing against the camera back. Before
putting the plates in the holder they should be backed with opaque paper attatched to
the glass, a slight touch of gum or paste at two corners is ample.
The changing is done in a dark bag the operation is simple.
The holder is
released by lifting the catch so that it falls back on its hinges the exposed plate is taken
out by catching it at two sides by the thumb & finger. The holder is closed & the
lid opened & the plate put in at back of the card board which is supplied with all of
the holders. When all are exposed the card board is at front and acts as a cover to
the plates.
The front of the camera is itself a shutter which may be made as a shutter seperately
or in conjunction with a camera of any form. In using it here I mount the lens inside
the box at back of shutter but the construction is the same whether used as a shutter
seperately or as part of this camera and whether at front of or behind the lens.
The especial part of the shutter which we claim as our invention is the mode of
applying the motive power by which the shutter is set ready for action without
carrying the exposing aperture across the lens. This is done by reversing the action
of the spring or springs which propel the shutter disc.
Suitable mechanism is arranged so that when in one position the springs will pull or
push the shutter disc in one direction & by moving the mechanisin the springs will pull
or push the shutter disc in the contrary direction. By the use of this shutter the plates
do not need to have a dark shutter in front of them and the only movement needed to
expose is to adjust the mechanism which propels the shutter disc and then at the
proper moment to press the spring or ball which releases it.
Dated this 26th day of October 1888.
S. D. MKELLEN.
J. D. MCKELLEN.

page_text: COMPLETE SPECIFICATION.
Improvements in Photographic Cameras.
the
SAMUEL DUNSEITH MCKELLEN, Photographic Engineer and JOHN DUNSEITH
MCKELLEN Photographic Apparatus Maker, 3 Chapman Street Hulme, Manchester,
do hereby declare the nature of this invention and in what manner
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
Our invention is intended specially to apply to cameras of the detective class and to
the shutters used therewith and which shutters can be used with lenses under ordinary
circumstances.
We construct the detective camera in the form of an oblong box, sliding in another
of the same shape if lenses which require to be. focussed for varying distances are
used, or if fixed focus lenses are used we construct the camera, by preference, of one
box only.
At one end of the camera we provide a space, I, which allows a dozen (or a less or
a greater number) of plates, m, to be inserted so that the front one being pressed
against the rebate, n, will be in focus with the lens. At the back of these plates a
door, o, is hinged, which being opened, the plates fall backward.at the top to allow the
exposed plate to be removed. The camera being then tilted forward the plates are.in
a position to allow the removed plate to be inserted at the back. The door being now
closed it forces a spring, or springs, against the plates which are now all pressed
forward, the front one being forced into focus, ready for next exposure. A piece of
cardboard should he put at back of the batch of plates, which cardboard, as they
are changed, works forward, till finally when all are exposed and changed, the
cardboard gets to the front, thus showing when the plates are done.
In the double body cameras. I mark figures, p, on the inner body, so that the outer
one, when drawn out to such figures, will carry the lens into correct focus with objects
at the distances in feet which are indicated by those figures, so that focussing, in the
ordinary meaning, is not required, and no ground glass is necessary. This focussing
can also be done by rack and pinion, or any mechanical contrivance which may be
found convenient.
.pro-
The shutter, A, forms the front of the camera, and can also be used as an ordinary
shutter. It is constructed so that the setting of it is done by reversing the position of
the motive power instead of by moving the covering parts. In using ordinary
shutters a sensitive plate cannot be left uncovered in a camera whilst the shutter is
being set, as the act of setting admits light through the lens into the camera, and would
spoil the plate. In our shutter the setting is done by reversing the position of the power.
Thus, an exposure having being made, and the lens being closed by one of the parts of
the cover, it is only necessary to reverse the direction of the power,.so that the.
pulsion will be in a direction contrary to the last position. This reversing, power
action can be applied to almost every kind of shutter now made, and can be done by
the use of spiral, or by helical springs, or by elastic bands, or by straight springs or by
hydraulic or pneumatic pressure. The way we prefer to use the invention in connec-
tion with this detective camera is as follows:-A is the front, or shutter. B is the
aperture which admits light to the lens. (is the cover, formed-like the wings of a
butterfly, working on its centre. D. E-E are spring catches which prevent the
wing from recoil, which might cause a double exposure. F is a spiral spring. G is
a spring carrier, to which one end of the spiral spring is hooked, and which works on
a shaft passing through the centre D on which the wing revolves. H is the pin
attached to the wing, to which the other end of the spiral spring is hooked. I is the
releasing lever which holds the shutter when the spring catch E-E' is withdrawn.
The action is as follows. When the spring carrier G is in a given direction the
tension of the spiral spring tends to pull the wing Cround in that direction. When
the releasing lever I is removed by pressure of the thumb, the wing revolves on its
axis, the middle open space passing over the lens and giving the exposure. When the

page_text: other part of the wing has arrived over the lens, one of the springs E-E falls into a
notch on the edge of the wing, and prevents recoil.
To re-set the shutter the spring carrier is turned to the opposite direction. In
passing the catch,-E or E'-it moves it out of the notch. This allows the wing to
move a little way forward. The catch now no longer holds the wing, but the releasing
lever now holds it, so that when pressure is applied to the releasing lever, it is lifted
away from the wing, which, being released, revolves as before and gives the exposure.
The shaft, on which the spring carrier rides, passes through the front of the shutter,
and terminates in a milled head for convenience in reversing. The amount of
turning round given to this head, regulates the amount of tension, by the amount
of stretching given to the spiral spring.
Instead of the spiral spring being attached to the spring carrier, riding on the shaft,
it may be attached to a sliding piece, which, sliding back and forward reverses the
direction of the power.
In our earlier cameras this was done, but the method first
described is found by experience to be the most convenient in manufacture, and is most
effective in working.
The mode of setting a shutter by reversing the direction of the power may be
applied to all sorts of shutters, and in numbers of ways, which can easily be understood
by any person conversant with the manufacture of such instruments, but which it
would be inconvenient to describe in detail. The foregoing description of the applica-
tion of the principle to the shutter which we use in the detective camera will suffice
for the present purpose.
The shutter forms the front of the detective camera, and the whole arrangement is
compact and easily carried about. The changing of the plates is done in an opaque
bag, and requires only a very little amount of time or skill.
In the annexed drawing Fig. 1 is a side view, Fig. 2 plan, of a detective camera
constructed according to this invention. In these views the camera is represented
drawn out to show the figures for focussing. Fig. 3 is a front view, and Fig. 4
back view of shutter or front of camera, the wing plate being at rest after exposure.
Fig. 5 shows the shutter as in Fig. 4, but set for exposure by reversing spring
carrier G, so as to give tension to spiral spring F. The dotted line represents the
position of the wing C after exposure, and at rest as in Figs. 3 and 4.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is,
1st. In a photographic camera the use of a recess for reception of plates in which
springs, actuated by closing of door of recess press against the plates and bring the
front plate into focus, and by opening of door allow the plates to fall backwards, in
the manner, and for the purpose substantially as herein before described.
2nd. The use of figures or other marks to indicate the focus for given distances,
substantially as herein before described.
3rd. In a photographic camera the use of a front which may be also used inde-
pendently as a shutter, in which the exposing aperture is always closed except at the
moment of exposure.
t
4th. The method of reversing the direction of the motion of the cover, or covers, of a
photographic shutter, by reversing the direction of the actuating power, said actuating
power being either of the form and description shown on drawings or by the applica-
tion of any convenient form of power.
S. D. MCKELLEN.
J. D. MCKELLEN.