IMPROVEMENTS IN THE FORMATION AND CONSTRUCTION OF PHOTOGRAPHIC CAMERAS
Year: 1886

page_text: I, JOHN EDWARD THORNTON, of New Lorne Street, Moss Side Manchester in the
County of Lancaster Printer do hereby declare the nature of my invention for
IMPROVEMENTS IN THE FORMATION AND CONSTRUCTION OF PHOTOGRAPHIC CAMERAS,
to be as follows;-
The improvements which are the subject of this invention relate to the form and
construction of photographic cameras and the object of my invention is to effect a
reduction in the weight of photographic cameras, by the avoidance of accessories
and external requirements or replacements of duplicates and loose parts.
In constructing a photographic camera according to my invention I form the
base board with an aperture or opening, the object of such opening being for
a twofold purpose hereinafter more definitely described, firstly for forming a
receptacle for the lens or lenses, and secondly, to serve the purpose of a tripod
head.
The front board or panel to which the lens is usually attached I form of the
ordinary shape externally but with a circular opening of a suitable size through
the centre. I fit into this opening a revolving panel or table, to which one, two or
more lenses are attached in such positions that by revolving the said table, either
one or other of the lenses as required may have a central position, and come
opposite centre of plate: The front board is supported between struts in the usual
way and with sufficient rise and fall to allow one of the lenses attached to front
board being placed opposite centre of either upper or lower half of plate: by these
means a lens of the size required may be used without detaching the unrequired
sizes of lenses from the camera, which thus remains always complete and ready
for use.
When the operator desires to pack the camera, the front board with the lenses
affixed, is laid down on the base board, the opening in the base board forming a
receptacle and packing space for the lenses, thus obviating the necessity for their
removal from the front board.
In order to retain the Kinear form of bellows, I make a slight extension on the
upper side of the first two or three laps.

page_text: To the edge of the circular opening in the base board, I attach firmly and
permanently a hollow or box shaped metal ring, with a groove or opening in the
said ring: this groove in the fixed metal ring form a receptacle for the upper ends
of the legs supporting the camera, around and upon which the camera revolves.
The upper ends of the legs are retained in their position in the fixed metal ring by
a spring or other suitable means.
'
The standards between which the front board is supported, are hinged at their
lower ends to a transverse bar: This transverse bar is made with V shaped or
other similar suitably formed ends which fit into corresponding recesses in the sides
of metal racks attached to base board, so as to slide backwards or forwards in
order to place the front board nearer to or further from the camera body for long
or short focus, as desired. These racks are formed with teeth both on their upper
and lower sides: A pinion working in the teeth on the upper side of racks causes
the transverse bar carrying front board with lenses attached to travel backwards
or forwards, and a pinion working in the teeth on the underside of racks operates
the sliding frame of base board in a similar manner.
When it is preferred to draw out or close the base board quicker than by
operation of rack and pinion, I withdraw the pinions from contact with the racks
by transverse pressure on the pinion spindle, and the base board may then be
drawn out or pushed in by hand: the pinions regain their previous positions by
means of a spiral spring, which retains them always in gear with racks, except
when purposely displaced.
In a central position on the underside of the camera body I attach a plate in
which I form a transverse slot: through this slot passes a set screw: the camera
body may obtain a lateral movement and also the required horizontal swing, and
be held firmly by means of the said set screw.
.
In place of the ordinary ground glass I use as a focussing screen a suitable trans-
lucent material wound on a spring roller which is fitted on one side of aperature
of camera body: the method of using this focussing screen is the same as an
ordinary spring blind, being held at one side by a fastener when required in use,
and winding itself on the roller when released.

page_text: Improvements in the Formation and Construction of
Photographic Cameras.
:
I JOHN EDWARD THORNTON of New Lorne Street, Moss Side Manchester in the
County of Lancaster Printer do hereby declare the nature of my invention for
IMPROVEMENTS IN THE FORMATION AND CONSTRUCTION OF PHOTOGRAPHIC CAMERAS
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
The improvements which are the subject of this invention relate to the form and
construction of photographic cameras, and the object of my invention is to effect a
reduction in the weight of photographic cameras, by the avoidance of accessories
and external requirements, or replacements of duplicates and loose parts.
In constructing a photographic camera according to my invention, I form the
front board or panel to which the lens is usually attached, of the ordinary shape,
and with a circular opening of a suitable size through the centre: I fit into this
opening a revolving panel or table to which I attach two or more lenses, in such
positions that, by revolving the said table, one or other of the lenses as required
may have a central position, and come opposite centre of plate: The front board is
supported between fork and with struts in the usual way, and constructed in such
a manner that while the said front board is prevented from having any pivotting
or swinging motion between the fork, sufficient rise and fall may be obtained
vertically to allow any one of the lenses which are attached to front board being.
placed opposite centre of either upper or lower half of plate.
By these means a lens of the size required may be used without detaching the
unrequired sizes of lenses from the camera which thus remains always complete
and ready for use: When the operator desires to pack the camera, the revolving
table or panel, with the lenses affixed, is reversed: the front board with the lenses.
attached is then laid down on the base board, the bellows forming a receptacle or
packing space for the lenses, thus obviating the necessity for their removal from
the front board: I do not attach the front board to the sliding frame, but in lieu
thereof I support the said front board between a fork, attached to angular side
sliding plates: for the purpose of readily attaching or detaching the fork to the
sliding plates, I form a stud or projection on each side of lower part of fork.
These studs fit into holes formed in flat springs attached to said sliding plates:
the springs retain the fork in position, and the fork is easily detached for closing
the camera by pressure on the springs: The angular side sliding plates travel
along grooves in the extension frame, and are actuated by a pinion working into
racks attached to the sliding frame: I form these racks with teeth on both their
upper and lower edges: A pinion working in the teeth on the upper side of racks,
causes the fork carrying front board with lenses attached to travel backwards and
forwards, and the extension frame is worked by the usual pinion underneath.
When it is preferred to draw out or close the base board or extension frame or
sliding plates quicker than by the operation of rack and pinion, the teeth of the
pinions are cut away for a portion of their length, and the pinions are withdrawn

page_text: from contact with the racks by transverse pressure on the pinions or pinion
spindles: the base board or extension frame, or sliding plates are thus free to be
drawn out or pushed in by hand. The pinions regain their previous position by
means of spiral or flat springs which retain them always in gear with racks
except when purposely displaced. In place of the ordinary ground glass I use as
a focussing screen a suitable flexible translucent material such as goldbeater's skin,
paper prepared with varnish or gelatine, parchment, or other suitable material,
wound on a roller with a spring attached, which I fit on one side of aperture of
camera body: the method of using this focussing screen is the same as an ordinary
spring blind, being held at one side by a fastener when required in use, and
winding itself on the roller when released, the requisite tension on the screen is
obtained by the spiral spring on roller.
In order that my invention may be clearly understood I have annexed three
sheets of drawings, which I now describe: In the several views contained
therein, similar letters refer to similar parts: Fig. 1, is side view and Fig. 2,
front view of camera constructed according to my invention with front board b, in
position and to which are attached lenses e, f and g: In these views the lens e is
placed opposite centre of camera back or plate but either one or other of the
lenses and g may be placed alternately in a central position by revolving the
table j. The fork which may be of any shape or form preferred supports
the front board b rigidly in a vertical position, but permits of the said front board
being raised or lowered vertically so as to place either of the lenses e, f, or g
opposite the centre of either upper or lower half of plate: The means I employ as
shown in these views is by a groove in the fork in which either two studs
placed at a distance apart, or an elongated projection on sides of front board serve
the purpose of a vertical slide, at the same time preventing any oscillating motion
in the front board b: Fig. 3 is a longitudinal section of camera: in this view the
front board b with the fork l attached, is disconnected from the extension frame t,
and with the revolving panel j reversed is laid down on the base board s, so that
when the camera body a is closed the lenses e, f and g occupy a position and are
packed within the bellows without being removed from the camera: The angular
sliding plates m support the fork and struts n, and travel with them along the
extension frame in grooves p, being actuated by pinion r and racks r. The
extension frame t is represented in Fig. 1. by dotted lines as being extended in the
usual way.
In Fig. 4 the camera is represented as contracted for a short focus by the
angular side sliding plates m. with the front board b attached having been moved
nearer to camera body by the pinion r working in racks r¹ causing the angular
plates m to slide in the grooves p: Fig. 5 is sectional plan on line A. B. Fig. 1.
Fig. 6 is back view of camera body a with a focussing screen h of suitable
translucent material attached to spring roller x.
Figs. 7, 8, and 9 are plan, transverse section, and elevation to an enlarged scale
of part of camera, showing grooves p for sliding plates m. and also a modification
of racks in combination with sliding plates, in which a narrower form of rack is
applied in lieu of broad rack as represented in Figs. 1 to 5.
In the several views, y is the flat spring into which the stud x¹ is fitted, as
herein before described.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed I declare that what
I claim is
1st. In a photographic camera, the combination with a front board of a revolving
panel to which two or more lenses are affixed, in the manner and for the purpose
as herein before described.
2nd. The method of attaching the fork carrying the front board of a photo-
graphic camera to angular side sliding plates, by means of flat, springs, for the
purpose, and substantially in the manner as herein before described."

page_text: 3rd. In the extension frame of a photographic camera, the use of a rack or racks,
with teeth formed on their upper and lower edges, and in combination therewith,
the bottom pinion ² and the extension pinion r actuating the angular side sliding
plates carrying fork, stretchers, and front board, substantially as herein before
described.
4th. The method of placing the pinions attached to base board or extension
frame, or sliding plates out of gear with racks in the manner herein before
described.
5th. In a photographic camera, the use of any flexible translucent material, such
as goldbeater's skin, paper prepared with varnish or gelatine, parchment, or other
similar flexible material, for focussing purposes, in lieu of the ordinary ground
glass, as herein before described.
6th. For the purpose of carrying the flexible translucent material for focussing
screen, and for obtaining the requisite tension on said screen the use of a spring
roller attached to camera body substantially in the manner herein before described.
Dated this 20th day of November 1886