IMPROVE- MENTS IN PHOTOGRAPHIC CAMERAS
Year: 1884

page_text: I, SAMUEL DUNSEITH MCKELLEN of 18 Brown St Manchester Watch Manu-
facturer & Jeweller do hereby declare the nature of my invention for IMPROVE-
MENTS IN PHOTOGRAPHIC CAMERAS to be as follows:-
My invention relates to the arrangement for focussing and is designed to
facilitate the use of lenses of different focal lengths In my arrangement I use a
base board which is that part of the camera which carries & supports all of the
other parts. This base board I make with two parlell rails or guides which are
fixed on one of its surfaces and extend the full length of the base board. Between
these rails I adjust a sliding frame on which I fix one or two or more toothed
racks which extend its full length This frame slides firmly & freely between the
guides so as to traverse the base board towards one end or towards the other end.
I make my base board to contain two pinions one at each end and placed so that
they are at right angles to the two parallel guides and at right angles to the racks
in the slide. These pinions are so placed so that they gear or take into the before
named racks so that by revolving them or one of them the sliding frame may be
made to traverse the whole length of the base board and to project nearly its full
length from either end as required Now if a camera body carrying the focussing
screen is attached to one end of the base board and the camera front carrying the
lens is attached to the opposite end of the sliding frame or vise versa, by means of
those two pinions the camera front may be moved as far from or as close to the
camera body as may be desired without detaching any part of the camera or
removing either body or front from those parts to which they are attatched Thus
if lenses of long focus are to be employed the pinion nearest the front will be
revolve to make the slide traverse in a direction away from the body of the camera
thus increasing the distance of lens from focussing screen and when short focus
lenses are used then the pinion nearest the camera body will be used to make the
slide travel between the guides in a direction towards the camera body thus
decreasing the distance between the lens & focus screen.

page_text: I SAMUEL DUNSEITH MCKELLEN of 18 Brown Street Manchester in the County
of Lancaster Watch Manufacturer and Jeweller do hereby declare the nature of
my invention for IMPROVEMENTS IN PHOTOGRAPHIC CAMERAS and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention relates to an arrangement for focussing in photographic cameras,
for the purpose of facilitating the use of lenses of different focal lengths.
In my invention, I uso a base board, which is the part of a camera that carries
and supports all the other parts.
This base board I construct with two paralell rails, or guides, secured to one of
its surfaces and extending the full length of the base board.
Between these rails I adjust a sliding frame, to which I attach one or more
toothed racks, which extend longitudinally the full length of the said sliding frame :
form this sliding frame so as to traverso firmly and freely between the rails or
guides on the liaso board, in a direction towards either end of the base board as
required In any suitable position on or in the base board, I attach two pinions or
toothed rollers: I place these pinions or toothed rollers, preferably one at each end
of the base board, and ut right angles to the paralell rails or guides, and also to the
toothed racks attached to them.
These pinions or toothed rollers, are so placed that they gear or take into the
toothed racks and by revolving the said pinions, the sliding frame is made to
traverse the whole length of the base board and to project nearly its full length
from either end of the base board as required: By this means a camera body
carrying the focussing glass being attached to one end of the base board, and the
camera front carrying the lens being attached to the opposite end, of the sliding
frame, or placed in relatively reversed positions, the revolution of one or other of
the pinions as before described, moves the camera front as far from, or as near to,
the camera body as may be desired, without detaching any part of the camera, or
removing either body or front from those parts to which they are attached.
If lenses of long focus are required to be usod, with a traversing arrangement
as herein before described, the pinion nearest the front board will be revolved, to
make the slide traverse in a direction away from the body of the camera, thus
increasing the distance of lens from focussing screen; When short focus lenses aro
required to be used, the pinion nearest the camera body will be revolved to mako
the slide traverse between the guides in a direction towards the camera body, thus
decreasing the distance between the lens and focus screen.
In order that my invention may be fully understood, I now describo the
accompanying sheet of drawings, reference being made to the figures and letters
marked thereon.
Similar letters refer to similar parts through the several views.
a, is the camera body, b the base board, c the front board, d, the bellows e the
sliding frame, f, the paralell rails or guides: g, and j, the pinions or toothed rollers:
g and the milled heads on shafts of pinions, by which the pinions are turned,
the toothed racks.

page_text: Fig. 1 is side elevation of a camera with camera body a, and front board c, at
right angles to base board b, and with the slide e, remaining in the same position
as before the camera was opened.
C,
is
Fig. 2 is side elevation of the same, but with the front board c, brought nearer
the camera body a, for a short focus lens, the slide e, to which the front board
attached being made to traverso in a direction towards the camera body a, by
means of the pinion g, and the racks h.
Fig. 3 is side elevation of a camera showing the slide e. with the front board c,
extending in a contrary direction for a long focus lens, being made to traverse by
means of the pinion j, and the toothed racks h.
Fig. 4 is end elevation of a camera,
Fig. 5 is plan of a camera with slido e, projecting, and the front board c,
brought nearer the camera body a, as represented in Fig 2.
Fig. 6 is an enlarged sectional end view, and Fig. 7 an enlarged sectional side
view of camera base board b, and slide e, showing the pinions and racks.
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 photographic camera, the use of two pinions for the purpose of giving
motion to the sliding frame carrying the front board and lens, or carrying the
camera body: such motion causing the front board and the camera body to
approach to or to recede from each other, by which means, either a short or a long
focus lens, may be used without detaching any part of the camera, or removing
either the camera body or the front board from those parts to which they are
attached, substantially as herein before described.
Dated this 20th dow of Wh