Improvements in Photographic Cameras.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Photographic Cameras.
I, LODEWYK JAN RUTGER HOLST, of 90, Damrak, Amsterdam, Holland,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to cameras of that kind adapted to carry a series of
sensitized plates in a change box or magazine.
According to my invention I divide the camera into two parts by an inclined
partition arranged between the objective and the magazine and adapted to support
a mirror which in conjunction with a ground glass screen, arranged on the top of
the camera, will form a focus finder. A movable cover is arranged over the screen
to prevent the latter from being too much exposed to the light.
Behind the partition are arranged a shutter and mechanism for moving the
mirror and shutter, and the partition is provided with an opening of such size that
the plate foremost in the magazine is fully exposed.
Means are provided whereby the mirror may be raised from the partition to
uncover the opening therein so that the light can reach the plate.
The shutter is a flexible band placed directly in front of the plate to be exposed
and designed to be wound on rollers, the lower of which is arranged in conjunction
with a spring which tends to cause the said roller to wind up the band from the
other roller onto which it is wound by hand. This band has two openings,
the upper of which is sufficiently large to allow of the passage of frames containing
the sensitized plates or films. The other opening is sufficiently large to effect the
instantaneous exposure of the plates and is at such a distance from the other
opening that the part of the band between the two openings completely covers the
plate. The band is sufficiently long below the second opening to permit of the part
containing this opening being wound on the upper roller.
The shutter is released from the upper roller by the device which raises the
mirror from the partition.
Means are also provided whereby the movement of the shutter band can be
automatically stopped when the unperforated part of the shutter between the two
openings in the same is directly in front of the exposed plate.
The plates, which are pressed forward in the magazine by a spring, are supported
at their lower edges against the pressure of the spring by a ledge and at their upper
edges by two approximately semi-circular plates forming the pallets of an escape-
ment and so arranged ou a shaft that, when the said shalt is turned to move one of
the semi-circular pallets out of the path of the foremost plate to allow the same to
fall after exposure onto the bottom of the camera the other will come in front of
the next plate to retain it against the pressure of the spring.
The shaft also releases the shutter, which has been automatically arrested, before
setting free the foremost plate.
A pivoted plate is arranged at the bottom of the camera down which the plates
can slide when cropping from the magazine.
Dated the 27th day of March 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.

page_text: довобларе Сашегар.
I, LODEWYK JAN RUTGER HOLST, of 90, Damrak, Amsterdam, Holland,
Engineer, 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 cameras of that kind adapted to carry a series of
sensitized plates in a change box or magazine.
In divided or mirror cameras as heretofore constructed the mirror was placed
with its upper edge so near to the back of the camera that its front edge could not
strike against the lens board when it was rotated upwards on its upper edge as a
pivot for the purpose of an exposure.
With such an arrangement, however, it is impossible to provide the camera with
a change box in which the plates are tilted as the exposed plate when tipped
forward on its lower edge would strike against the mirror with its upper edge
thereby preventing further movement on the part of the plate.
When, however, the mirror is placed so far forward that the exposed plate can
be tipped forward behind it the said mirror cannot be rotated on its upper edge as
in this case it would strike against the lens board. For this reason a particular
lifting arrangement is required by means of which the mirror can be pressed against
the upper focussing screen of the camera in such a manner that it does not hinder
the tilting of the plate nor strike against the lens board. To this end, therefore,
I cause the mirror to be raised and lowered by means of levers arranged laterally
in the camera and having their pivots behind the said mirror. This arrangement
of levers serves also to operate the shutter situated directly in front of the plate to
be exposed.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawings, in which
-
Figure 1 is a longitudinal section of a caniera made according to my invention,
and,
Figure 2 a cross section of the same.
According to my invention I divide the camera into two parts by an inclined
partition M arranged between the objective and the magazine and parallel to the
line bisecting the angle made by the exposed plate and the ground glass screen M³
of the focus finder arranged on the top of the camera. This angle is generally 90°
but it may be greater or less. The distance of the partition M from the
said bisecting line is such that the surface of a mirror M, attached to the
said partition and reflecting the rays of light therefrom, is exactly in the said
bisecting line.
The objective is arranged in any suitable manner in the camera in front of the
partition and may be focussed by any convenient method but preferably by a
movable partition L' connected to the front of the camera by a leather bellows to
prevent light penetrating into the camera.
The ground glass screen M2 is fitted to a projecting part of the camera in such
a position that a vertical line through its centre meets the mirror M at the same
point as the optical axis of the objective. The length of this vertical line is equal
to the distance of the point of intersection of the vertical line and the optical axis
from the plate to be exposed.
A hinged cover M³ is arranged over the ground glass screen M² to prevent the
same from being too strongly illuminated.
The partition M' is provided with an opening of such size and shape that the
plate behind the same, foremost in the magazine, is fully exposed to the light rays
when the mirror is raised from the partition.

page_text: Two springs B, B are attached to the back of the mirror M near the edges of
the opening in the partition, the said springs being connected to two levers B³, B³
one of which (that shewn in the drawing) is bent. These levers are suitably
pivoted at E and as the pivot of the bent lever would come in the path of a
toothed wheel hereinafter to be described, it is carried by a suitable support from
the side of the camera on which the toothed wheel is situated, but on the other
side of the camera it is fitted directly to the side. Two links B, B4 are pivoted,
at their upper ends, to the levers B, B and at their lower ends to levers B³ which
are fixed to a rotatable spindle B³ passing through the sides of the camera.
An
arm B² forming a continuation of one of the levers B³ is pivoted to a vertical
rod B¹ which passes through the top of the camera and is provided at its upper end
with a knob or button E. A spiral spring wound on the vertical rod B¹ tends to
press the latter continually upwards.
Between the upper part of the mirror and the bent lever B³ I arrange a small
spring B7 which tends to draw the mirror towards the said lever. B³.
The shutter is a flexible band G placed directly in front of the plate to be
exposed and designed to be wound on two rollers R and R³ and to pass over the
guide roller R' interposed between the two rollers R and R³.
This band G is provided with two openings, the upper of which is sufficiently
large to allow of the passage of the frames containing the sensitized plates or films.
The other opening is sufficiently large to effect the instantaneous exposure of the
plates and is at such a distance from the other opening that the part of the band
between the two openings completely covers the plate. The band is sufficiently
long below the second opening to permit of the part containing this opening being
wound on the upper roller.
The lower roller R is placed underneath the magazine or plate box and is free
to rotate on the spindle R² one end of which passes through the side of the camera
and is provided with a knob or button. On this spindle R2I fit a spiral spring.one
end of which is fastened to the spindle and the other end to the roller R, the said
spring tending to wind the band on the roller R in the direction of the arrow shewn :
in Figure 1, and the roller being provided with a ratchet and pawl arrangement.to
prevent the same from rotating backwards.
The upper roller R³ to which the upper end of the shutter band is fastened also
projects through the side of the camera and is provided with a knob or button to
enable the band to be wound on the roller. The said roller is also provided in the
interior of the camera with a disc having a single tooth which engages with a
spring pawl D².
This pawl is provided with a downwardly projecting arm the lower extremity of
which is bent outwards so that it can be pressed downwards by the free end of the
bent lever B³.
A small toothed wheel is mounted on the upper roller R³, between the said
toothed disc and the side of the roller, and gears in a second toothed wheel D
provided with a laterally projecting pin D¹. This pin is so arranged that it can
rotate freely when the band G is wound on the upper roller R³. The toothed
wheel D has at least six times as many teeth as the wheel on, the roller R³ which
gears with it.
The mechanism for changing the plates is operated by a shaft or spindle C
which passes through the magazine in the direction of the length of the camera,
the end of the shaft, which projects through the camera, being provided with a
handle (3. The front end of this shaft C is provided with two approximately
semi-circular plates or discs C¹ and C² arranged to act like the pallets of an
escapement. The frame which contains the foremost sensitized plate presses
against the back of the front disc C¹, the said frame lying with its bottom edge
against two stops N3 and N, Figure 2, which are fixed to the bottom of the plate
-box.
The rear semi-circular disc, C2, which projects in a direction opposite to that
of the front disc C₁, is separated from the latter by a distance equal to the width.
'

page_text: of a plate frame and it is also somewhat tapered at the end so that it can easily
pass between the two front frames. When this disc C2 is turned fully downwards
it relieves the front plate from the pressure of the spring, arranged at the back of
the plate box to force the plates outwards, the front plate being at the same time
released from the front disc C¹.
As seen in Figure 2 two levers C³ and C are arranged transversely across
the plate magazine. The inner end of the lever C³ rests on an eccentric fixed
to the shaft C between the two discs C' and C2 whilst its other end is bent down-
wards and rests on the spring pawl D2 when the latter engages in the toothed
disc. The inner end of the lever C also rests on an eccentric on the shaft C,
which eccentric is so shaped that when the said shaft is rotated through the
first 90° by means of the handle C³ the lever C does not move, but when the
bandle is further rotated the inner end of the lever is raised so that the arm N¹
of the plate N is turned backwards (thereby assuming the position shewn by the
dotted lines in Figure 1) by means of the rod N2 which is fixed to the outer arm
of the lever and to the arm N' of the plate N. A spring C' arranged upon the
lever C tends to keep the latter always in contact with the eccentric.
The operation of the apparatus is as follows:-
For instantaneous photography the knob of the roller R³ is turned until the
whole of the free length of the shutter band G is wound up on the same and the
lower unperforated part of the shutter completely covers the sensitized plate.
During the winding up of the shutter first the larger and then the smaller
opening passes in front of the plate which, however, is not acted upon by the
light rays as the mirror M completely closes the opening in the partition M¹.
The winding of the shutter band G on the roller R³ causes the spring of the
roller R to be wound up so that when the shutter is released it is again wound on
the roller R by the action of the said spring. The tension of the spring can be
regulated as desired by means of the knob on the spindle R².
By pressing down the button B the mirror M lying on the partition M¹ is raised
and assumes the position shewn in the dotted lines in Figure 1. The mirror then
completely closes the opening in the top of the camera and leaves the opening in
the partition M¹ free for the passage of the light rays. On further pressing the
knob B the springs Be are compressed.
the same.
The short arm of the lever B5 which engages with the bent portition of the spring
pawl D2 when the mirror is shifted to its upper position presses the said pawl D2
downwards so that it releases the toothed disc on the roller R³ thereby releasing
the shutter which is then wound up on the roller R by the action of the spring on
The toothed wheel on the roller R³ simultaneously causes the toothed
wheel D to rotate until the pin on the side of the latter comes in contact with the
inner edge of the shorter arm of the lever B. The movement of the shutter is
then stopped in such a position that the unperforated part of the band between the
two openings is directly in front of the exposed plate. The exposure is now
finished and by relieving the button B of pressure the mirror M is allowed to drop
on to the partition M¹ thereby covering the opening of the same. As soon as the
springs B, on the release of the button B, press on the lever B the latter releases
the pawl D2 which again engages with the toothed disc on the roller R³. As the
lever B³ must go still further before it is released by the pin D¹ it is evident that
the pawl engages with the ratchet wheel before the pin Di is set free. When the
mirror drops on to the partition the shutter remains in the position which it assumed
after the exposure.
In order to change the plates the shaft C is half turned by means of the
handle C3 in the direction of the arrow shewn in Figure 2. The shorter arm of
the lever thereby presses the pawl D2 downwards so that the shutter band is
again set free, but as the mirror is in its lower and the lever B in its inoperative
position the toothed wheel D meets with no resistance so that the shutter is not
prevented from unwinding until the large opening is situated in front of the
plate..

page_text: As soon as the handle C³ begins the second half of its revolution the plate N is
turned downwards by means of the lever C and the rod N2 as hereinbefore
explained until its upper edge lies against the lower edge of the plate box. The
rotation of the handle C³ causes the front disc C¹ on the shaft C to release the
exposed plate whilst the edge of the rear disc C passes between the first and
second plates. The front exposed plate is then only held at its lower edge by the
two stops N³ and N₁ and is tipped forward into the bottom of the apparatus on.
tilting the latter.
The handle is then returned to its original position whereby the plate N again.
assumes its vertical position, the spring pawl D' is set free by the lever C5 and
again engages in the toothed disc on the roller R3 and the rear disc C³ at the same
time sets free the second plate which is then pressed forward against the back of
the front disc C' by means of the spring at the back of the plate box so that the
second plate is ready for exposure.
When it is desired to operate by time exposure it is only necessary to give the
handle C³ a half turn so that the shutter is freed and completely unrolled from
the roller R³ whereby the large opening comes to lie in front of the exposed plate,
and then to raise the mirror M from the opening in the partition M' by depressing.
the button B. The exposed plate is then tipped forward in the manner herein-
before described.
Having now particularly described and ascertained the nature of my said inven--
tion and in what manner the same is to be performed, I declare that what I
claim is
1. A divided or mirror camera wherein the change box mechanism is so-
arranged that the mirror instead of being rotated on its upper edge is raised or
lowered by lateral levers (B) the pivots (E) of which are situated behind the
said mirror so that the latter can be arranged so near the lens board that the
exposed plate can be tipped forward behind the mirror substantially as described.
2. A camera of the kind described in Claim 1 having a flexible shutter provided
with a small opening for instantaneous exposure and with a large opening for
time exposure through which latter opening the sensitized plates can be passed,
the said shutter being operated by means of a lever (B) connected with the
mirror, which lever, when passing to its upper position, releases a pawl (D').
holding a roller (R³) so that the flexible shutter is rolled up and the narrow
opening passes in front of the plate until a pin (D¹) on a wheel (D) actuated by
the roller, comes in contact with the lever (B) thereby again stopping the
shutter until the pawl (D2) again engages with the roller when the mirror is.
lowered substantially as described.
3. A camera of the kind described in Claim 1 in which a lever (C³) operated
by the changing of the plates sets free the pawl (D2) of the roller before the
front plate is released so that the shutter is rolled up further in order to bring
its large opening in front of the plate either for the purpose of time exposure
or for changing the exposed plate which is tipped forward through the said.
opening substantially as described.
Dated the 23rd day of December 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant..