Improvements in Photographic Cameras.
Year: 1894

page_text: Date of Application, 6th Jan., 1894-Accepted, 10th Feb., 1894
COMILELE DI MULTICATION.
Improvements in Photographic Cameras.
I, WILLIAM FITZ-HARRY CURTIS, of Langrick, Boston, Lincolnshire, Clerk
in Holy Orders, do hereby declare the nature of the said invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accompanying two
sheets of drawings, and to the letters and figures marked thereon, that is
to say:
The first part of this invention relates to improved means for directing and
controlling the movements known as "swinging the back" of a camera. Heretofore,
ao far as I am aware, when the back of a camera has been made to swing, it has
been caused to pivot on hinges or centres placed at the side and top or bottom of
the swinging parts in such positions that there is considerable disturbance of the
focus when the back is swung. Now the object of this part of my invention is to
provide means whereby the swinging of the back of the camera shall take place
on imaginary or virtual axes which pass through a point or points at or near the
centre of the sensitive film when the latter is in position in the camera, whereby
the disturbance of focus for any given angle of swing is reduced to the least
possible.
In the drawings hereto annexed, Figure 1 is a side elevation of so much of the
back part of a camera, with my improved swinging back applied thereto, as is
necessary for the elucidation of the invention, and Figure 2 is a plan of certain of
the parts shown in Figure 1.
In Figure 1 the point X represents the position of a horizontal imaginary axis
coincident, or nearly so, with and parallel to the sensitive surface of the film at or
near the middle of its height; this axis is the one on which the back of the camera,
and consequently the film, oscillates or swings, according to my invention, in a
vertical plane. The point in Figure 2 represents the position of a vertical
imaginary axis coincident, or nearly so, with, and parallel to the sensitive surface
of the film at or near the middle of its width; this axis is the one on which the
back of the camera, and consequently the film, oscillates or swings, according to my
invention, in a horizontal plane.
It will be understood that the axes X and * are in such positions that they
cannot be established as physical axes, and the object of this part of my invention
is to employ them as virtual axes by so constructing and arranging the swing
back that it may be swung or oscillated on these virtual axes notwithstanding the
absence of real or physical axes.
The rear portion of the body of the camera is divided into three separate parts
or frames marked respectively A, B and C in the drawings. The rearmost part or
frame A is adapted to receive the dark slide containing the sensitive film the
surface of which coincides more or less nearly with the imaginary axes X
and as before described. The middle part or frame B has the part or
frame A connected to it; and is itself connected to the front part or frame C
which is hinged at D, at each side of the camera, to the usual running plate E by
which the back of the camera can be adjusted forward or backward on the base-
board F. The part or frame C is held rigid by means of a strut G at each side of
the camera, pin-jointed at one end to the running plate E and secured at the other
end to the frame C by the clamping nut H, the slot G' in the strut G allowing the
said frame C to be folded down on the base board F when the camera is out
of 100

page_text: The frame A is connected to the frame B by plates I attached at the top and
bottom of each side of the frame A and provided with slots 1'. Screwed studs J
secured to the frame B pass through these slots, and are fitted with clamping
nuts K. The slots I¹ in the plates I are segments of circles described from the
centre X. L is a plate secured at each side of the frame A and provided with a
circular segmental slot L' also described from the centre X. A stud or block M
secured to the frame B passes through this slot and is preferably provided with a
guiding head M'.
The frame B is connected to the frame C by slotted plates P secured to the top
and bottom of the frame B, the slots P¹ being segments of circles described from
the centre. Qare screwed studs secured to the frame C and passing through
the slots P', and provided with clamping nuts R. As there is not room for screwed
studs and clamping nuts at the lower slotted plates P, their slots take over short
studs that come flush or nearly so with their lower surfaces. S is a plate secured
to the frame B and provided with a circular segmental slot S₁ described from the
centre *. T is a stud or block secured to the frame C and provided with a guiding
head T¹.
It will now be understood that on slacking back the clamping nuts K, the
frame A can be swung round the imaginary horizontal axis ✗ to the extent
permitted by the slots 11 of the plates 1, the slot L' in the plate L co-operating
with the slots 1' to guide the frame A in its circular movement round the
axis X. When the frame A has been placed in the desired position, it can be
clamped there by the clamping nuts K. Similarly, on slacking back the clamping
nuts R the frame B, and with it the frame A, can be swung round the imaginary
vertical axis * to the extent permitted by the slots P¹ in the plates P, the slot S'
in the plate S co-operating with the slots P¹ to guide the frame B in its circular
movements round the axis *. When the frame B has been placed in the desired
position, it can be clamped there by clamping nuts R.
The outer edge of the slotted plate L or S, or of either of the slotted plates I
or P, may be formed as a toothed rack or sector and a pinion be arranged to gear
with it for the purpose of swinging the frames A and B instead of swinging them
by hand.
I do not limit myself to arranging the parts so that the imaginary or virtual
axes occur exactly at the centre of the height or width of the sensitive film as the
horizontal axis may be somewhat above, or below, the centre, and the vertical axis
somewhat to one side or the other thereof if preferred, and either or both somewhat
in front of or behind the surface of the sensitive film.
It is obvious that the slotted plates I and L, regulating the vertical swing of the
frame A, may be secured to the frame B, and the studs J and M to the frame A.
Also that the slotted plates P and S, regulating the horizontal swing of the frame B,
may be secured to the frame C, and the studs Q and T to the frame B, the
slots L' and S' in the plates L and S being modified accordingly.
The bellows forming the body of the camera are attached inside the frame A
and extend to the front board of the camera; they are not shown in the drawings
but may be of the ordinary and well known construction.
The second part of the invention relates to improved means for securing the
camera with uniformly distributed pressure on the top of its tripod or other
support, and for enabling it to be turned easily into any desired position thereon.
For these purposes 1 employ arrangements of the kind shown in Figures 3, 4 and 5
of the drawings in which Figure 3 is a plan of a tripod top with my improvements
applied thereto, the camera being removed, and Figures 4 and sectional elevations
on lines 1-1 and 2-2 respectively of Figure 3. U is the top of the tripod stand,
and V the base-board of the camera. This base has a circular opening formed
through it the edge of which is bevilled as shown at V. U' are two pieces
adapted to slide on the upper surface of the tripod top U, their outer edges Us are
bevilled and shaped as circular arcs corresponding to the opening in the base

page_text: board V of the camera.
The slides U₁ are movable to and from the diametral
line 2-2, and may be guided in such movements by any suitable means; in
Figure 3 the guiding means consist of slots Us formed in the said slides and guide
blocks U secured in the tripod U and passing through the said slots, the heads of
screws U preventing the slides U' from rising. W is a right and left handed
traversing screw turning in bearings W₁ secured to the tripod top U and taking
into nuts W secured to the slides U W is a crank. formed in the screw W and
provided with a connecting rod handle W* by which the said screw can be rotated
in either direction.
It will now be understood that on turning the screw W in one direction, the two
slides U will be drawn towards each other and towards the diametral line 2-2,
the opening in the base V of the camera can then be passed over the slides U' so
as to rest on the tripod top U, the sides of the slides U being cut away as shown
in Figures 3 and 5 to clear the bevilled edge of the opening in the base V. On
turning the screw W in the opposite direction, the slides U¹ are moved away from
each other and from the diametral line 2-2 until their bevilled edges U' bear
firmly against the bevilled edge of the opening in the base board V of the camera
whereby the latter is wedged down and clamped firmly on to the top U of the
tripod. By slackening back the slides U¹ the base V, with the camera upon it,
can be turned into any required position on the tripod top, and be then secured in
that position by tightening up the slides.
If preferred, one of the pieces U' may be fixed permanently to or formed with
the tripod top U, the other only of the two pieces being adapted to slide, and in
that case only one part of the screw W would be required.
In the drawings two slides U¹ only are shown, but it is obvious that three or
more may be employed radiating from the centre; in that case, however, the radial
movement of such slides can be better effected by means of a cam plate with slots
acting on pins in the slides, than by a traversing screw or screwe.
Instead of mounting the clamping slides on the top of the tripod or other
support and making a corresponding circular opening in the base of the camera,
the slides may be mounted on the underside of the base of the camera and a
corresponding circular opening or recess be made in the top of the tripod or other
support.
The usual pins for receiving the legs of the tripod are not shown in the drawings
but they may be fixed to the underside of the tripod top U in the usual manner,
though I prefer to hinge them thereto so that when not in use they may fold down
and offer but little projection.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
clain is :-
First. The mechanism for enabling the back of a camera to swing on imaginary
or virtual horizontal and vertical axes which pass through a point or points at or
near the centre of the sensitive film, consisting of slotted plates the slots in which are
segments of circles described from the said imaginary or virtual axes, and of
clamping devices, arranged, combined and operating substantially as described with
reference to Figures 1 and 2 of the drawings.
Second. The devices for securing the camera on its tripod or other support, and
for enabling it to be turned thereon, consisting of one or more radially acting slides
mounted on the top of the tripod or other support or on the underside of the base
of the camera and provided with bevilled edges which fit and bear against the
correspondingly bevilled edge of a circular opening in the base of the camera or
in the top of the tripod or other support substantially as described.
Third. The devices for securing a camera on its tripod or other support and for
enabling it to be turned thereon consisting of one or more radially acting clamping
slides engaging with the edges of a circular opening or recess formed in the base of

page_text: the camera or in the top of the tripod or other support, the said slide or, slides
being operated by a traversing screw, substantially as described with reference to
Figures 3, 4 and 5 of the drawings.
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W. FITZ-HARRY CURTIS,
Per W. H. Beck,
115, Cannon Street, London, Agent.
W. FITZ-HARRY CURTIS,
Per W. H. Beck,
115, Cannon Street, London, Agent.