Improvements in Apparatus for Changing and Focussing and Exposing Photographic Plates or Films.
Year: 1892

page_text: Date of Application; 25th Feb., 1892
Complete Specification Left, 7th Nov., 1892-Accepted, 10th Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Changing and Focussing and
Exposing Photographic Plates or Films.
I, THOMAS EDWARD HEATH, of Oakridge, North Road, Cardiff, Manager of
Fuel Works, do hereby declare the nature of this invention to be as follows:-
:
This invention is intended principally to be used for that class of cameras known
as hand cameras but it may be used for others. It enables a large number of plates
to be carried in a very small camera and the plates to be selected and exposed in
any required order and it allows a focussing screen being used when desired and the
focussing to be adjusted either to the picture shown upon the screen or to an
estimated distance or to what is known as "fixed focus" and it also allows of an
approximately equal exposure being given all over the plate or a greater exposure
being given to the foreground than to the sky and I am enabled to use a rising front
and swing back.
1.
:
.7
In order that my invention may be better understood I will explain how I should
apply it for taking the ordinary "quarter plates " and assume the lens to be a
Rapid rectilinear of 4" inches equivalent focus. For this size I construct a rect-
angular camera box which need only be about 6 inches long 5 inches wide and
7 inches high and yet it will carry about two dozen plates besides a ground glass
focussing screen. If a lens of longer focus be used the camera box must be longer
but then more plates can be carried. In the upper half of this camera box I have
the exposing chamber. I fix the lens-to the front wall and at the back I have a
door which is light tight when closed. Along this exposing chamber travels an
exposing frame which is carried by a base plate which is pierced with a slot so
shaped as freely to admit a sensitive plate. The sides and top of the exposing
frame are grooved so as to allow the plate to slide freely in and to hold it approxi-
mately in position. The base plate travels in suitable grooves which extend from
end to end on either aide at the bottom of the exposing chamber. To the base
plate I attach at the front and at the back bands of leather or other suitable
material which may be stiffened by narrow strips of wood. These leather bands
extend to the grooves on either side of the exposing chamber and slide in them so
that all light from the exposing chamber is excluded from the lower half of the
) Caméra box. In the lower part of the camera and extending from very nearly under
the back of the lens to nearly to the plane of equivalent focus I have a store box
which is grooved on either side to hold the plates. For the size under consideration
the store box may be about 3 inches long so that it will hold about 24 sensitive
& one focussing plates. The bottom of the store box has a light tight door
through which the plates are inserted.
:
W
:
The leather bands which pull the exposing frame too and fro are carried over
suitable rollers all round the lower half of the camera box and below the storage
box. The end of each band is here secured to a plate and the two plates can be
drawn together by a bolt or otherwise. The plates also carry pointers which slide
in a long slot at the bottom of the camera and the bottom of the camera-may
conveniently be formed by doors hinged to each side and leaving this slot when the
doors are closed. Along the slot I have a marked and numbered scale which
corresponds with the grooves in the store box and the scale extends further and is
marked to show the position of the focussing screen. By pulling the pointers
5 backwards or forwards the exposing frame is moved in a like degree but in an
opposite direction and thus any required plate can be selected and if the camera is
inverted it will fall into the exposing frame. The camera being then turned on its
side the exposing frame can be moved back to focus position. The ground glass

page_text: "
plate can be selected and the door at the back of the exposing chamber being
opened the picture can be focussed by moving the pointers backwards or forwards
the position of the pointers on the scale is then noted, the door closed, the ground
glass returned and a sensitive plate inserted and the pointers moved back to the
position noted. This plan of focussing is only convenient when the camera is firmly
held upon a stand--when it is held in the hand it is more convenient to use what
is known as "fixed focus or to estimate the distance of the principal object. For
this purpose I provide a screw which passes through a bearing in the door at the
back of the exposing chamber which carries on its inner end a flat plate which is
adjusted so that it will just make contact with the back of the sensitive plate when
the latter is in the plane of "fixed" or equivalent focus and the screw is screwed
home on its bearing-and the distance of the object which is in exact focus when
the screw has been moved through one-two three or more revolutions is found by
experiment and noted for future guidance. The storage box must not extend so
far as to be under the slot of the exposing frame when the latter is at equivalent
focus but below the focussing range must be a plane surface making a light tight
joint. It is advisable to blacken about of an inch on the top and bottom of the
focussing plate and to keep it in the nearest groove. The front of the camera
which carries the lens is made so as to rise when required sliding up in suitable
grooves which may be notched at intervals to permit removal and it has a circular
recess cut in it in which works a thin disk with a drum on the middle to which two
cords or wires are attached and wound in opposite directions. The disk can be
revolved upon suitable bearings. The cords are carried down to opposite ends of a
rocking lever passing freely through holes therein and thence over guides to the end
of a lever or trigger which is attached at right angles to the rocking lever-and
which extends a little below the bottom of the camera front. The cords are tied or
made fast to the trigger in any suitable manner. I have a spring which engages in
suitable catches to prevent the trigger being accidentally pulled over. The trigger
may be pulled over by the finger or by a spring or elastic band for rapid exposures.
The disk is perforated so that when the trigger is pulled fully to one side or fully
to the other side the lens is completely covered but between these points it is
more or less open and upon one side of the disk I shape the perforation so that
the exposure is approximately equal all over the plate whilst on the other side the
perforation is so shaped as to give more exposure to the foreground than to the
sky. If one side of the disk has been in use and it is desired to use the other side-
and the trigger is fully over on one side-the disk is held firmly and the cords are
untied and the trigger can then be pulled over (the cords sliding through the holes).
Then the cords are pulled tight and again. secured to the end of the trigger when it
will be found that the other half of the disk is now in use. There are suitable
stops in connection with the rocking lever or trigger which prevent its ever pulling
the disk more than half a revolution.
The exposing frame may be attached to the base plate by suitable springs at
each side which normally keep it at right angles thereto but allow of the exposing
frame being pulled over to the front or to the back by suitable cords or other
devices.. may have a set screw or other catch to prevent the leather band from
moving when required. I have a slot in the top of the camera box with a sleeve
attached lined with velvet through which the diaphragms (which are pierced upon
each end of a long flat plate) are let down into the lens and there may be a loose
apron secured to the back of lens to insure perfect darkness. Films can be used in
suitable sheathes as well as plates-and if desired plates can be used in sheathes in
which case the storage box will not require grooves but to be covered at the top
except for a slot at each end. The plate in its sheath being raised by a suitable lever,
rack or other device into the exposing frame and when used returned by gravity
to the other end. This does not allow the plates to be selected conveniently.
Dated this Twenty-fourth day of February 1892

page_text: Improvements in Apparatus for Changing and Focussing and
Exposing Photographic Plates or Films.
I, THOMAS EDWARD HEATH of Oakridge, North Road, Cardiff, Manager of
Fuel Works 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 is intended principally to be used for that class of cameras known
as "hand cameras" but it may be used for others and I find that for small sizes it
is practically as good when used upon its stand as an ordinary "stand camera" and
more convenient to work. It enables a large number of plates or films to be
carried in a very small camera and the plates to be selected and exposed in any
required order and it allows of a focussing screen being used when desired and the
focussing to be adjusted either to the picture shown upon the screen or to an
estimated distance or to what is known as "fixed focus" and it also allows of an
approximately equal exposure being given all over the plate or a greater exposure
being given to the foreground than to the sky and I am enabled to use a rising
front."
$6
My invention is illustrated by Figures one to ten on the accompanying sheets of
drawings, like letters of reference indicating corresponding parts in the respective
figures.
Figure 1 is a longitudinal section of camera.
Figure 2 is a front elevation of camera.
Figure 3 is a section of the shutter (which is not shown in section in Figure 1).
Figure 4 is a front elevation of shutter with part of the front removed so as to
show the gearing.
Figure 5 shows the perforated disk as it may be shaped when the shutter is used
in front of the lens.
Figure 6 shows the perforated disk as it may be shaped should the shutter be
required to work behind the lens.
Figure 7 is a cross section of camera.
Figure 8 is a plan showing the tops of base plate and slotted plate.
Figure 9 shows the gripping contrivance which is screwed to the top of a tripod
to hold the camera.
Figure 10 is a section of camera with ungrooved store box; the rising front with
shutter and lens being removed..
In order that my invention may be better understood I will explain it as applied
to a camera for taking the ordinary "quarter" plates with a Rapid rectilinear lens
of 4 inches equivalent focus.
A is a rectangular camera box about 6 inches long-5 inches wide and 7 inches
high and is capable of carrying two dozen "quarter" plates (or films in suitable
sheathes) besides a ground glass focussing screen. If a lens of longer focus be
used the camera box A must be longer but then more plates can be carried if
desired.
In the upper half of the camera box I have an exposing chamber B. I attach
the lens C to the front wall D and at the back I have a door E which is light tight
when closed (the strips of velvet or other suitable material for making the needful
light tight joints are represented in the drawings by thick black lines). Along
the exposing chamber B travels an exposing frame F which is carried by a base
plate G which is pierced with a slot H so shaped as freely to admit a sensitive
plate. The sides and top of the exposing frame F are grooved so as to allow the
plate to slide freely in and to hold it approximately in position. The base plate G
travels in suitable grooves I which extend from end to end on either side at the
bottom of the exposing chamber B. The base plate G is attached to a tail piece J

page_text: which passes outside the camera box A through a suitable opening K which is lined
with velvet and cloth or otherwise made light tight, but as an additional precaution
I have an apron of velvet K' attached to the back of the base plate and suspended
from hooks on the top of the exposing frame F so as to cover the back of the
sensitive plate. The tail piece J has a hinged joint J' so that the part which
projects on the outside of the camera can be made to lie down in a recess at the
back of the camera box. L is a slotted plate which is attached at the front and at
the back to bands of leather M (or other suitable material) which may be stiffened
by narrow strips of wood glued across. The slot in the plate L is covered by a
sliding door N which kept in position over the slot by springs O (see Figure 8)
but which may be pushed back until stopped by suitable stops P. These leather
bands M extend to the grooves Q on either side of the exposing chamber and slide in
them so that all light from the exposing chamber is excluded from the lower half
of the camera box. In the lower part of the camera and extending say from under
the back of the lens C to nearly the plane of equivalent focus I fix a store box R
which is grooved on either side to hold the plates. The store box may be about
3" inches long and it holds 24 sensitive plates (or films in sheathes) and one focussing
plate. The bottom of the store box R has a light tight door S through which
the plates are inserted. The leather bands M are carried over suitable rollers T
all round the lower half of the camera box and below the store box R. The end
of each band is here secured to a plate U and the two plates can be drawn together
by a bolt V. The plates U also carry pointers W which slide in a long slot X at
the bottom of the camera and the bottom of the camera may conveniently be formed
by doors hinged to each side and leaving this slot when the doors are closed. Along
this slot I have a scale Y (see Fig. 1) which I prefer to mark in series of five, cut
alternately on either side, as it can then be more easily read. The scale corre-
sponds with the grooves in the store box R. No. 1 of the scale being the mark
nearest to the front of the camera corresponding with No. 1 groove which is situated
in that part of the store box nearest the back of the camera..
When for example
the two pointers W are pulled so that the No. 13 mark on the scale is exactly mid-
way between them then the slot in the slotted plate L will be immediately over
number 13 groove in the store box (see Fig. 1). I have also a scale Z upon the tail
piece J which I prefer to make by drilling holes through it (also in series of five)
in such positions that a peg a inserted in say for example, number 13 hole (see
Figure 1) will stop the tail piece J from being pushed in further than will bring
the slot H in the base plate G exactly over number 13 groove in the store box; the
peg a then coming in contact with a plate & fixed to the back of the camera box.
Whilst the base plate G is being pushed over the number 13 groove it first comes
in contact with the sliding door N of the slotted plate L and pushes it back
against the spring O until stopped by the stops P. If the slotted plate is
not over No. 13 groove but (as generally happens) over a lower number
it pushes it forward until it is immediately over and no further (being
stopped by the peg a). If the camera is then inverted No. 13 plate
will fall from the store box through the slotted plate L and through
the slot H in the base plate G into the exposing frame F and (still keeping
the camera inverted) the tail piece is pulled back carrying the exposing frame
into the focussing range. If the slotted plate L happens to be further on
than number 13 groove (say for example No. 15 plate had been last used and
returned to store box) it must first be moved back to No. 13 groove by pulling the
pointers W forward along the scale Y. (This must only be done when the
exposing frame is in the focussing range and it is not often necessary to refer to
the scale Y as long as the pointers are pulled forward sufficiently.) It is evident
that any plate can be selected in the same way as described for number 13 and the
plates may be exposed in any order so that several kinds of plates or films can be
carried and used to suit the subject. To prevent mistakes I fill the holes Z in the
tail piece J with coloured wax corresponding to the kinds of plate in the store
box for example, white, ordinary; red, extra rapid; green, isocromatic plates &

page_text: so on. The peg a pushes the wax out when a plate is changed and I can tell at a
glance what plates are used. The ground glass plate (which I find it convenient
to keep in No. 25 groove) can be selected and the door E being opened and the
velvet apron K¹ pulled down the picture can be focussed by moving the tail piece J
backwards or forwards. For this purpose I provide a screw c which passes through
This
a bearing d below the opening K through which the tail piece J comes out.
screw c carries on its outer end a flat plate e which is adjusted so that it will just
make contact with the tail piece J when the sensitive plate (or ground glass) is in
the plane of "fixed" or equivalent focus and the screw is screwed home on its
bearing and the distance of the object which is in exact focus when the screw has
been moved through one-two or more revolutions may be found by experiment
and marked down for future guidance or as shown on the drawings (see Fig. 1
and 10) the screw may be made of sufficient pitch to enable one revolution to equal
the ordinary focussing range and a scale of distances can be marked round the flat
plate e. In focussing with the ground glass and the camera upon the stand the screw
may be screwed in or out until the most satisfactory focus is found. In any case
when the focus is settled the focussing plate (if it has been used) is returned to its
place in the store box without altering the screw c and a sensitive plate being
selected and the tail piece J brought down upon the flat plate e the sensitive plate
will be in true focus. I have a spring which presses with sufficient force against
the back of the sensitive plate to keep it pressed against the front of the exposing
frame F when in the focussing range. This spring fis attached to the back of the
camera so that it can be turned out of the way when required. The store box R
must not extend so far as to be under the slot H of the exposing frame F when the
latter is at equivalent focus but below the focussing range must be a plane surface
or plate g which also serves to make a light tight joint. The plates should be
returned to the store box R as soon as convenient after exposure. To do this the
camera is inverted and the tail piece J pushed in to the peg a which will have been
left in the proper hole-and if the camera is now turned the right way up the plate
falls back into the store box. If by chance the peg a has got misplaced it can be
discovered by referring to the scale Y which the proper hole is. The rule for
changing plates is that when the exposing frame is empty the tail piece should
only be moved with the camera the right way up whereas if it has a plate in it the
tail piece should only be moved with the camera inverted. When filling the store
box in the dark room it is necessary to see that no plates which are so badly cut or
so thick that they will not work quite easily are put in but if that is seen to there is
no trouble afterwards. Occasionally however it may be necessary to give a tap or
shake to the camera to start a plate.
In order that the camera may be readily lifted from the stand without moving
the latter I have a gripping contrivance or vice (see Figure 9) which screws on to
the top of the tripod, and which extends and closes sufficiently to grip the camera
whether the latter is the usual way up (for taking horizontal pictures) or upon its
side (for taking vertical pictures). The camera can thus be very readily adjusted,
so much so that I find that it is quite easy when I have taken one vertical picture
to take a second so that the two pictures form a stereoscopic pair by changing the
plate and putting the camera down again upon the stand without shifting the latter
but seeing that if the first picture was taken with the left side of the camera up the
second is taken with the right side up so that the lens occupies on the second
occasion a position about 3 inches from what it had on the first time.
The front wall D of the camera which carries the lens C is made so as to rise
when required (it rises either way that is either for vertical or for horizontal
pictures) sliding up in suitable grooves and it has a circular recess i cut in it in
which is fitted the shutter case which I prefer to make in metal as I found that
if the rising front wall D, which is of wood, be used to form the shutter case
trouble is caused by the wood warping. The shutter is shown separately in
Figures 3-4-5 and 6 (and it may of course be used separately for another camera

page_text: if required. It is supposed to be contained in the rising front wall D of the camera
shown in Figures 1 and 2. In the shutter case i¹ works a thin disk j (see Figure 5)
with a drum k in the middle which may be actuated by cords or wires as described
in my Provisional Specification but which I prefer to actuate by toothed gearing
instead of cords and my present description is for that. The disk ; can be
revolved upon a suitable bearing 1. The drum k has any convenient number of
teeth cut round its circumference and I have rather more than half as many teeth
to gear therewith cut upon the end of a rocking lever m. I have a trigger n which
is attached at right angles to the rocking lever m and which extends through a
suitable opening in front of the camera. I have a spring o which presses up two
pawls o¹ which engage alternately with suitable catches o² attached to the rocking
lever m and which prevent its being accidentally pulled over or rebounding.
The pawls may be either of them depressed by the projecting buttons o³ and both
buttons may be held down when required by the hooks o. When one of the
buttons o³ is depressed the trigger n may be pulled over by the finger or by an
elastic band p for rapid exposures. A spring may be used if preferred but I find
the most convenient plan is to have elastic bands of different degrees of strength.
The disk is perforated so that when the trigger is pulled fully to one side or fully
to the other (in which position it is firmly held by the pawls) the lens is completely
covered but between these points it is more or less open and upon one side of the
disk I shape the perforation so that the exposure is approximately equal all over
the plate whilst on the other side the perforation is so shaped as to give more
exposure to the foreground than to the sky (see Figures 5 and 6). If one side of
the disk has been in use and it is desired to use the other side and the trigger is
fully over on one side; the disk is held firmly and the trigger is pushed down until
the teeth are out of gear-to enable this to be done the pawls are first held down
by the hooks o and then the sliding frame q to which the rocking lever m and
pawls and spring o are attached all slide down together in suitable guides. The
downward pressure being continued the trigger is pushed over and the pressure is
released when a spring pushes the sliding frame up and the teeth of the rocking
lever come again into gear. There are stops s which prevent the teeth from
coming too deep into gear. It will now be found the other side of the disk is in
There are suitable stops t which prevent the rocking lever m ever pulling the
disk through more than half a revolution.
use.
20
For general purposes it will suffice to divide the disk into two parts as described-
but for special ends more than this may be needed and it can be divided into any
number of parts if the gearing of the drum and rocking lever are made to suit and
the perforations may be shaped in any desired way. Also instead of having two or
more openings in one disk or plate they might be perforated in two or more plates
arranged one in front of the other each having besides the properly shaped per-
forations a sufficiently large opening to be held over the lens when that particular
plate is not in use. The disk should be carefully balanced and it is desirable that
it should be made of aluminium so as to be as light as possible. If desired other
suitable contrivances instead of a rocking lever may be employed to actuate the
disk and the stops and catches may act directly upon the disk.
T
Films can be used in the camera described if suitable sheathes of the same
outside size as a sensitive plate be employed to hold them and the film cut to fit.
If desired plates can be used in sheathes. In this case which is illustrated by
Figure 10-the storage box u has no grooves but is covered at the top by a plate v
except for a slot w at the end near to the back of the lens and another slot which
should be situated at the plane of equivalent focus. The end plate in its sheath is
carried up through the slot into the exposing frame F by a sliding shutter y
which works in suitable grooves on either side of the store box and which is the
same thickness as a plate in its sheath and the top of which when pushed home fills
the slot and is flush with the top of the plate and which extends through a
suitable light tight slot z across the bottom of the store box. If desired this sliding

page_text: shutter may be worked by a rack and pinion but I prefer for small sizes to push it
up by hand.
upon
The plate being pushed up into the exposing frame F is carried into the proper
focussing position as before described by pressing the tail piece J down the
screw plate e after exposure the tail piece J is pushed in until the slot in the base
plate G is over the slot to when it is stopped by the sliding door N coming against
the stops P. If the sliding shutter y be now pulled down the plates in the store.
box u will slide back and allow room for the exposed plate to fall into the store
box u through the slot w. As it is evident that plates cannot be selected upon this
plan without great trouble, if a focussing screen be required it should be kept in a
suitable frame which can be introduced through the back door E. This camera.
has not got to be inverted.
I may have one of the usual finders to attach to the camera, but if so the ground
glass should be marked so as to show the picture when the front is raised or when
lowered. I find however it is much better to work with spirit levels of which I
have two, of the ordinary circular construction, one for horizontal and one for
vertical pictures; because, having a rising front, I can get the horizontal line of
each picture at the hight which is most suitable and still keep one camera level so
that the perspective is correct and I find there is no difficulty about pointing the
camera in the right direction. I have tried both finder and level but I find it is.
practically impossible to keep the eye on both and therefore it is better not to use
the finder. A view meter however is a help as a separate instrument.
The lens stops may be on a quadrant plate operated by a spindle passing through.
the rising front (see Fig. 2).
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. In a photographic camera the combination and use of a fixed store box for
holding photographic plates or films having suitable grooves and arranged to extend
say from about the plane of the back of the lens to about the plane of equivalent.
focus with a flexible band excluding light from the same but allowing any required
plate to pass through a suitable slot; suitable means of bringing this slot over any
required plate; an exposing frame and suitable mechanism for moving the same to a.
position accurately over the required plate; and means for carrying the plate selected
to any required focussing position and returning it to the store box all substantially
as herein before described and illustrated in Figures 1, 7 and 8 of the accompanying
drawings.
2. In photographic cameras the use of a store box with a slot at each end and
without grooves for carrying photographic plates or films in suitable sheathes and
fixed to the camera so as to extend if desired from nearly under the back of the:
lens to the plane of equivalent focus in combination with a sliding shutter or rack
or other suitable contrivance for raising the end plate in its sheath from the store
box into an exposing frame without inverting the camera and with suitable.
mechanism for carrying the plate so raised in the exposing frame to any required
focussing position and returning it through the slot at the other end of the store
box substantially as herein described and illustrated by Figure 10 of the accom-
panying drawings.
3. In a photographic camera the combination and use of a disk or plate or plates
moveable across the lens and perforated with two or more openings shaped so as to
vary in any required manner the exposure of any part of the sensitive plate or film
with a rocking lever or other suitable contrivance for actuating the same; suitable
means for connecting and disconnecting the same and suitable stops and catches for
stopping, holding and releasing the same; all arranged so that any required per--
foration can be readily moved across the lens and the disk or plate stopped and
held automatically to cover the lens before and after exposure substantially as.

page_text: herein described and illustrated by Figures 1, 2, 3, 4, 5 and 6 of the accompanying
drawings.
4. The arrangement of photographic apparatus as herein described and illustrated
in the accompanying drawings.
..
Dated this Fourth day of November A.D. 1892.
THOMAS EDWARD HEATH.