Improvements in Plate or Film Holding Changing Backs or Slides for Photographic Cameras.
Year: 1892

page_text: Date of Application, 16th Dec., 1892
Complete Specification Left, 18th Sept., 1893-Accepted, 21st Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Plate or Film Holding Changing Backs or Slides
for Photographic Cameras.
I THOMAS SAMUELS, of Monken Hadley, in the County of Middlesex,
Gentleman do hereby declare the nature of this invention to be as follows:-
My invention relates to multiple plate or film holding changing boxes or dark
slides of that kind in which a number of sheathed plates or films are placed in front
of one another in a box like chamber and are transferred in succession from one end
of the series to the other through the medium of a flexible light-tight bag enclosing
the open side or end of the said box, the plates or films either facing all one way or
being placed back to back in double sheaths so as to form a double series facing in
opposite directions according as the box or holder has a shutter at the front only or
at both front and back.
My present improvements relate particularly to the means whereby the transfer
of the sheathed plates from one end to the other of the series is effected, and they
have for their object to facilitate the operation of transferring the plate and admit
of the flexible bag being so reduced in dimensions that it may be folded wholly
within the open mouth of the changing box which it encloses and be itself enclosed
and protected when thus folded by a hinged lid. My improvements also have for
object to guard against double exposures.
According to my present improvements the lifter or frame whereby a plate to be
transferred is partially withdrawn and caused to project sufficiently into the bag to
enable it to be seized by the fingers, is adapted to act not only as a sliding lifter but
also (when it has fulfilled its purpose as a lifter) as a lever to transmit a backward
pressure to the whole series of plates in order to force them backwards sufficiently
to make room in front of them for the plate which has just been been brought from
the other end of the series. This lifter is constructed of a U-shaped frame having
cranked and inwardly projecting lugs at the ends adapted to engage with the
sheathed plate to be withdrawn, the side members of the lifter being guided by the
sides of the plate chamber and when the lifter is drawn out to its full extent
working on fulcra thereon or the side members of the lifter may be jointed and
work on those joints as fulcra. The mouth of the flexible bag is affixed within the
aperture of the plate-holding box and the bag is attached at a suitable point to the
cross-member of the lifter so that when the lifter is drawn out and swung slightly
backwards the bag will be distendod and brought to the proper position to enable
the plate raised by the lifter to be seized through the bag, raised wholly within the
latter, and transferred to the other end of the series, without shifting or relaxing the
grip until the operation is completed.
The means whereby the swinging of the lifter in the forward direction is caused
to transmit a backward pressure sufficient to cant the whole series of plates
backwards to admit of the introduction of the plate to be transferred, comprise
intermediate levers pivoted to the sides of the plate chamber on which the side
members of the lifter act, and which levers in turn engage with or terminate at
their opposite ends in presser pieces bearing against the front flanges of the fore-
most plate sheath and presenting inclined surfaces to the incoming plate so that
after having made room therefor, they as well as the intermediate levers by which
they are actuated will be restored to normal position by the act of introducing
said plate.
In order to guard against double exposure, especially in the case of a changing
box or slide having a shutter at both front and back and containing a double series
of plates placed back to back in double sheaths as above mentioned, I provide an

page_text: automatic or partly automatic locking device whereby a shutter having been once
drawn cannot be drawn a second time until the hinged door which closes in the bag
has been opened which of course is only done for the purpose of obtaining access to
the bag and transferring an unexposed plate to position for exposure. This
automatic fastening consists of a latch adapted to permit the withdrawal of the
shutter a first time but to oppose a second withdrawal of the shutter on the latter
being closed and to be itself locked or engaged by a latch or detent mounted on the
inside of the door and which may be in such operative connection with the fastening
of the door that the act of unfastening and opening the door restores the locking
device to its initial condition of disengagement or freedom so that it no longer
obstructs the withdrawal of the shutter. Each shutter would be provided with
such a locking device, both controlled in the same way and by the same, or by
independent, means.
Dated this 16th day of December 1892.
THOMAS SAMUELS,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Plate or Film Holding Changing Backs or Slides
for Photographic Cameras.
I THOMAS SAMUELS of Monken Hadley in the County of Middlesex,
Gentleman, 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 :-
My invention relates to multiple plate or film holding changing boxes or dark
slides of that kind in which a number of sheathed plates or films are placed in front
of one another in a box like chamber and are transferred in succession from one
end of the series to the other under the protection of a flexible light-tight bag
which encloses the open side or end of the said box, the plates or films either facing
all one way, or being placed back to back in double sheaths so as to form a double
series facing in opposite directions according as the box or holder has a shutter at
the front only, or at both front and back.
My present improvements relate particularly to the means whereby the transfer
of the sheathed plates from one end to the other of the series is effected, and my
improvements have for their object to facilitate the operation of transferring the
plate and admit of the flexible bag being easily extended and so reduced in
dimensions that it may be folded away wholly within the open mouth of the
changing back which it closes, and be itself. enclosed and protected when thus
folded by a hinged lid. My improvements also have for object to guard against
double exposures.
The invention will be described with reference to the accompanying drawings
which show a changing back or dark slide provided with shutters at both front and
back, and in which
Figure 1 is a vertical section of the apparatus on line 1-1 Figure 2, and
Figure 2 a similar section on line 2-2 Figure 1. Figure 3 is a top view of the
changing back with the cover removed. In these three figures the bag and the
sheaths and plates are omitted for the sake of clearness.
Figures 4 and 5 are sections of the back similar to Figure 2 but containing the
sheathed plates.
Figure 6 is a top view of Figure 4.
Figure 7 shows an underside view of the cover for the mouth of the back provided
with the means for guarding against double exposures.
Figure 8 is an edge view of a double sheath such as would be employed with a
back having both front and rear shutters as represented in the drawing.

page_text: According to my present improvements the lifter or frame A whereby a plate to
be transferred is withdrawn from the back and caused to project into the bag to
enable it to be seized by the fingers, is adapted to act, not only as a sliding lifter,
but also (when it has fulfilled its purpose as a lifter) as a lever to transmit a
backward pressure to the whole series of plates in order to force them backwards
sufficiently to make room in front of them for the plate which has just been brought
from the other end of the series. This lifter is constructed of a U shaped
frame mounted at the rear of the changing back and having inwardly projecting
ends a which, in the normal position of the frame are received in recesses a' in the
base of the changing back so as to be clear of the lower edges of the plates which
are, for the purpose of being raised, successively brought into position over the
ends a of the frame. The side members A' of the lifter are curved near their lower
ends as shown, and they are contained in recesses in the sides of the chamber and
enclosed therein by cover plates B, a slot b being cut therein to give passage to the
inwardly turned ends a when the lifter is fully raised with a plate, as shown in
dotted lines in Figure 5. C is the flexible bag whose mouth is affixed at one edge c
to the interior of the chamber near its mouth, and whose other three edges are
attached to a U shaped piece D pivoted in the mouth of the box at d and received
in a recess d in the mouth of the box. By swinging back this piece D together
with the bag, the end of the box is exposed for fitting the apparatus with sheathed
plates or removing them therefrom. The bag is attached to the cross member A of
the lifter, as shown in Figure 5, so that when the lifter is drawn out and swung
slightly backwards on the inwardly turned ends a as fulcra, (as shown in dotted
lines) the bag will be distended and brought to the proper position to enable the
plate p raised by the lifter to be seized through the bag, wholly raised within the
latter, and transferred to the other end of the series, as shown in full lines, without
shifting or relaxing the grip until the operation is completed.
The means whereby the swinging of the lifter in the forward direction is caused
to transmit a backward pressure sufficient to cant the whole series of plates back-
wards to admit of the introduction of the raised plate, comprise a pair of intermediate
levers E, pivoted at e to the inner sides of the chamber, on which the side members
of the lifter act, and a pair of presser pieces F pivoted at f to the sides of the
chamber with which the levers E engage, said presser pieces F being received in
recesses at the front of the box and adapted to bear against the front flanges of the
foremost plate sheath p' when the lifter A is canted forward to make room for the
plate being transferred as hereafter described. The plates are held up to the focal
planes by means of flat springs p* interposed between two single sheaths P' P³, the
space between these two sheaths being sufficient to admit of the canting of the
foremost plate P' as above described. These springs are shown as attached to
the back of one of the single sheaths and they are adapted to yield to pressure
when the plate is forced down between the foremost plate and the front of the
chamber.
The apparatus is operated as follows:-
The changing back having been filled with the sheathed plates as shown in
Figures 3, 4 & 5 care being taken that the plates bearing the springs are placed at
the front of the series away from the lifter and the foremost and rearmost plates
having been successively exposed, the rearmost pair of sheathed plates p* are
brought to the position shown in dotted lines in Figure 5 by grasping the loop or
tab a' of the bag and raising and canting the lifter A backwards as seen.
The pair
of sheathed plates are then further raised until the sheath clears the rest of the
plates in the chamber and the sheath is then moved towards the front of the
chamber and placed above the first sheath of the series. The lifter rocking on its
inwardly turned ends a as fulcra is then moved forward thereby oscillating levers e
and causing the pressers F to force the plate P2 back to the position shown so as to
admit of the introduction of the lower edge of the sheath P* between P' and the
front of the box. The lifter A is then moved back to the vertical position so as to
release the pressers F and the sheath P* is forced down to the bottom of the
'

page_text: chamber, the lifter and the bag at the same time being returned to its original
position within the box. This sheath P* in moving down comes in contact with
the inclined surfaces of the pressers F and returns them along with levers E to
their normal position. The other plate contained in sheath P is now ready for
exposure as well as one of the plates which has been brought into position at the
back of the box, and so on until all, or the required number of plates have been
exposed. The bag after each operation of changing the plates is packed away
into the space in the mouth or end of the box and the locking device with which
the hinged cover G hereafter described is provided is re-set and the cover closed
down over the mouth of the changing back and secured as seen in Figure 4.
In order to guard against double exposure and to ensure the changing of the.
plates when exposed more especially in the case of a changing box or slide having
a shutter S at both front and back and containing a double series of plates placed
back to back in double sheaths as above mentioned I provide a locking device
whereby after two exposures have been made the shutters are prevented from being
again opened.
This fastening consists of latches or buttons H on the top of door G mounted on
pivots which extend through the cover and are provided on the inside of the
cover G with notched plates I which are fixed to the pivots. These plates are
controlled by spring pressed pawls J pivoted at j. to the cover and whose nibs j¹
enter notches in the plates I as bereafter described. is a hexagonal cam on
the inside of the cover G formed in one with a milled head K and adapted to press
against and separate the tail ends of the levers J to force nibs out of
engagement with plates I when desired. This cam preferably has upon its inner
face numbers from 0 to 5 which are successively exposed through a corresponding
opening in the cover as the cam rotates constituting an indicator of the number of
changes made. is a spring serving to return buttons H to their normal position.
Now assuming that the back is charged with plates as in Figure 4 and closed by
the cover Gas in Figures 4 and 6, the latches occupying the position shown in said
figures said latches oppose the accidental opening of shutters S. In order to
expose a plate the corresponding latch is turned sufficiently to withdraw its nib h
from the path of the shutter, which may then be raised and lowered, the nib j of
pawl J engaging the notch and preventing the button H from being turned back-
wards. If then it be desired to again lock the shutter to prevent a double exposure
the button H is turned until the pawl J engages notch 2 in which position the nib ³
lies in the path of the shutter and effectually closes it until the cover is removed.
The removal of the cover is intended to serve as a reminder that new plates must
be brought into position for exposure.
•
Owing to the form of notch when the cover is closed the pawl cannot be
released from the notch as it can from the notches !. To do this the door G must
be opened and the pawl J withdrawn from the notch by rotating the milled
head K, the spring bearing on the nose of the plate I returning button H to the
position shown.
Although I have described the device with reference to one shutter only, cach
shutter is provided with such a locking device, both being either controlled by a
button K or by independent means.
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,
1st. The employinent in a multiple photographic plate or film holding changing
back or slide, of a U shaped frame enclosed within a bag secured to the open end
of the changing back and adapted to act, not only as a lifter for the sheathed
plates, but also as a lever by which a backward movement may be imparted to the
plates in the chamber to make room in front of the plates for the plate brought
from the rear of the series, substantially as specified.
2nd. In a multiple photographic plate or film holding changing back or slide,

page_text: the combination with a lifter for the plates consisting of a U shaped frame having
inwardly turned ends sliding in grooves in the sides of the chamber and enclosed
within and attached to a light tight bag secured to the mouth or open end of the
changing back of the pressers adapted to be operated by the lifter through inter-
mediate levers for the purpose of canting the plates, substantially as and for the
purpose specified.
3rd. A photographic plate or film holding changing back or slide consisting of a
box or chamber having front and rear shutters, an open end protected by a light-
tight bag a U shaped plate lifter attached to the bag and adapted to be canted to
act as a lever, pressers pivoted to the chamber and intermediate levers the whole
substantially as described and shown in the drawings.
4th. A locking device for the shutter of a photographic changing back or slide
consisting of a latch on the door or cover capable of being rotated from the outside
in one direction only and which is adapted when partially rotated to permit of the
withdrawal and closure of the shutter a first time and when further partially rotated
to oppose a second withdrawal of the shutter, the latch being itself engaged by
mechanism which can only be released when the door or cover is opened substan-
tially as and for the purpose specified.
5th. The herein described locking device for the shutter of a photographic
changing back or slide consisting of the pivoted latch H mounted on the outside of
the door or cover and made in one with the notched plate I arranged on the inside
of the door or cover, the said notched plate being controlled by the spring pressed
pawl J substantially as and for the purpose specified.
Dated this 18th day of September 1893.
THOMAS SAMUELS.