Apparatus for Changing Plates in Photographic Cameras or Dark- backs in Daylight, without the use of a Room or its Equivalent.
Year: 1898

page_text: Date of Application, 19th Aug., 1898
Complete Specification Left, 30th Mar., 1899-Accepted, 2nd June, 1899
PROVISIONAL SPECIFICATION.
Apparatus for Changing Plates in Photographic Cameras or Dark-
backs in Daylight, without the use of a Dark Room or its
Equivalent.
CHARLES LOUIS HETT, of Springfield, near Brigg, in the County of Lincoln,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
In carrying out my invention each plate is placed seperately in a light tight
bag of leatherette or other suitable material. The bags are about double the
length of the plates and are closed by a double crease in opposite directions.
The film side of the plate is distinguished by a mark on the outside of the bag.
As a further protection from light the bags may be enclosed in outer bags or
boxes. For placing the plates in the camera or dark back I employ a special
transfer chamber about the length of the plates employed.
The section of this chamber is a flat oval, fitted internally with suitable guides
to receive the plate. One end is open, the other is closed by a sliding or
revolving shutter; which will be mentioned later. When it is desired to place
a plate in the camera or dark back, the outer crease of one of the bags, containing
a plate, is turned down and the open end of the transfer chamber is inserted in
the mouth; taking care that the mark on the bag, indicating the film side of the
plate, corresponds with a similar mark on the transfer chamber. An elastic ring
preferably of india rubber and circular in section, which is previously placed on
the transfer chamber is rolled over the mouth of the bag, holding it tightly and
effectually excluding the light. The transfer chamber is now attached to the
camera or dark back and held uppermost. The bag is now turned up vertically.
This opens the remaining crease and the plate drops into the camera or dark back
where it is fastened by a tightening screw in the back or equivalent contrivance.
The action is simply reversed for the removal of the plate.
The connection between the transfer chamber and camera or dark back may be
made on any safe plan. For instance that provisionally protected by W. E.
Newton on behalf of Henry Cook see Spec. No. 1526-67. Several cameras and
magazines of this design are still in existance. Another suitable arrangement
is very similar to the modification of W. S. Rogers Patent No. 239-90 which is
employed in the Key camera. In the case of this latter arrangement, however,
the transfer chamber must remain attached to the camera or dark back until
the plate is returned to it; unless other means are provided for excluding the light
during its absence.
I do not confine myself to these arrangements which form no part of my in-
vention.
I am also aware that several plans have been devised for transferring sensitive
plates from light-tight bags to the camera or dark back and vice-versa.

page_text: The novelty in my arrangement consists in the use of a transfer chamber about
the length of the plates employed. This chamber although preferably detachable
may be permanently fixed and simply turn down parallel to the axis of the camera.
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Apparatus for Changing Plates in Photographic Cameras or Dark
Backs in Daylight, without the use of a Dark Room or its
Equivalent.
I, CHARLES LOUIS HETT, of Springfield, near Brigg, in the County of Lincoln,
Mechanical 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:-
In carrying out my invention each sensitive plate is placed in a seperate light-
tight bag of leatherette or other suitable material. These bags are about double
the length of the plate and are closed by a double crease in opposite directions.
The film side of the plate is distinguished by a mark on the outside of the bag.
As a further protection from light the bags when loaded may be stored in outer
bags or boxes. The latter being generally the more convenient plan.
For placing the plate in the camera or dark back I employ a special transfer
chamber about the length of the plate employed or rather more.
The section of this chamber is a flat oval with suitable grooves to receive the
plates. The upper end is open and the lower end is closed by a sliding or re-
volving valve. The form of this valve and the connection between the transfer
chamber and the camera or dark back may be varied. But I prefer the arrange-
ment shown on the drawing. This is a modification of Prov. Specification
No. 1526 A.1). 1867 taken out by W. E. Newton on behalf of Henry Cook.
In the accompanying drawing my invention is shown as applied to a camera.
In the case of a dark back, but little modification is required beyond the intro-
duction of the ordinary sliding shutter.
Fig. is a back view of the camera with the transfer chamber in position for
inserting a plate. Half is in elevation; and half in section.
Fig. 2 is a longitudinal section. Fig. 3 is a plan half in section and half with
the transfer chamber removed. Fig. 4 is a plan of an automatic arrangement
for pressing the plate against the front of the frame and thus bringing the film
into register.
A is the plate when in the bag B, which is placed on the transfer chamber C,
and secured thereto by means of an india rubber ring d.
This ring is circular in section so that it may readily be rolled from the lower
part of the transfer chamber onto the mouth of the bag or in the reverse direction.
A represents the plate when in position in the camera or dark back. e and e
are hooks on the transfer chamber, which when the latter is in position, enegage
with the lugs f and f, and hold the transfer chamber securely to the camera or
dark back. g, is a valve which closes the lower end of the transfer chamber,
when removed from the camera or dark back. is a valve which closes the opening
in the camera at the same time. and are small springs which keep these
valves from shaking open. 7 is the frame containing the plate when in the camera
or dark back.
The mode of operation is as follows:-
When it is desired to place a plate in the camera or dark back, the outer crease

page_text: of one of the bags containing a plate is straightened out; and the open open end of
the transfer chamber inserted into its mouth, taking care that the mark on the
bag, indicating the film side of the plate, corresponds with a similar mark on the
transfer chamber.
The india rubber band d, which has previously been placed on the transfer
chamber, is rolled over the mouth of the bag holding it tightly and effectually
excluding the light. The transfer chamber is now attached to the camera or dark
back, by applying it thereto and sliding it in the direction of the lens.
As the transfer chamber moves it carries with it the valve i, and thus opens the
aperture in the camera or dark back. While the transfer chamber moves the
valve remains stationary, and thus the lower end of the transfer chamber is
opened. The bag B is now turned vertically upwards. This opens the remaining
crease and the plate drops into the camera or dark back. The film is brought into
register by a light tight screw through the back, by any suitable arrangement
now used for a similar purpose, or by the arrangement shown on the drawing
which I now describe. m, is a set screw tapped into and therefore moving with
the valve i n, is a yoke jointed at each end to levers and o.. There is a stop
on each end of the yoke, which bears against the levers and o and the yoke
is thus prevented from falling too low. 2 and p are two springs bearing on the
levers and o and pressing them towards the plate A!. r is a centre pin carrying
the two levers o and o. s is a stay, a duplicate of which not shown on the drawing
is on the other side. These stays support the frame carrying the plate and also
form packings between the cover platest and and the frame, is a packing for
the like purpose. The effect of sand is to seperate the cover plates and t
from the frame and to leave room for the working of the levers o and o.
The transfer chamber is shown in position and the pin m acting through the
yoken holds the lower ends of the levers o and clear of the plate A¹.
0,
The transfer chamber is removed by sliding it backwards away from the lens,
until the hooks c and e, clear the lugs f, and f. This action closes the valves
and . The valve in closing leaves the yoken, free to move away from the lens
and consequently allows the springs and to press the lower ends of the
levers o and o onto the back of the plate A¹. Thus bringing the film into register.
The removal of the plate, is effected by replacing the transfer chamber and
reversing the above operations.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that I am
aware that plates have been transferred from bags to cameras and I make no
general claim as to such transfer. I declare that what I claim as novel is: —
The use of a transfer chamber of the nature described for the purpose of trans-
ferring sensitive plates from light-tight bags, each containing a single plate to
a camera or dark-back. This chamber may be removable, as described, or simply
turn parrallel to the axis of the camera.
Dated this 28th day of March 1800