IMPROVEMENTS IN PORTABLE PHOTOGRAPHIC CAMERAS
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I FREDERIC WILLIAM HART, of 8 and 9 Kingsland Green London, in the County
of Middlesex; Manufacturor of Scientific Apparatus, do hereby declare the nature
of my invention for IMPROVEMENTS IN PORTABLE PHOTOGRAPHIC CAMERAS to be
as follows:-
I first construct the front framework of the camera in square or other
rectangular form, such framework having a revolving flanged disk of the greatest
diameter the framework will permit, such disk has an opening through it; half its
width below the centre to near the circumference, the width being of such
dimension as will permit the lense tube to be centrally placed and moved freely
along the opening to near the circumference, on this revolving disk I place a slide
diametrically over the opening and of such length and width as will well cover
the opening when the centre of the slide is brought over the opening near the
circumference; on this slide the Lense is to be mounted.-I fix the disk and slide
in any desired position by means of screws or cam clamps with my Improved
folding disk heads to such screws or cam clamps. The construction :-On the
shank is a disk of metal and across the diameter is hinged a half disk of like
thickness which when raised enables, the screws, cams or racks and pinions to be
actuated; when folded down the whole does not project from the body of the
Camera more than one eighth of an inch thus, permitting close packing whereas
the screw heads at present in use project half to three quarters of an inch thus
preventing compact packing.-The back framework and the flexible extending
body is constructed as usual with the exception that I employ my folding disk
heads to all clamping screws and pinion heads. The advantage in using the said
disk heads will now be seen in my main Improvements to obtain extended range
for Lenses of long focus.-I shut the body-as above described-up quite close,
together with one or more dark slides or a magazine plate holder included and
form around them a casing, embracing the Top, Front, Bottom and Back, three of
these rectangles being hinged and the forth angle secured by lock, bolts or hooks :-
This my Improved base board when unfolded is made rigid by triangular bolts of
metal Steel or Bronze preferred-sliding in groves in opposition to the hinges,
means being provided by, the enclosing plate for taking up wear so as to ensure
continuance of the utmost rigidity.-The camera body frames slide to and fro on
D

page_text: this base board, being kept parallel by side guides in the ordinary manner.-On
the top face of the base board 1 employ two short lengths of rack-when weight
is of moment-say one sixth of the length of the base board, the solid base of
which is V, or half V, on the sides with corresponding counterparts for them to
slide in the base board. The end of each portion of rack has a spring detent pin
to fix them at any part of the base board corresponding to the focus of the lense
in use at the time. Where weight is not an object the metal rack may be fixed
the entire length and cut at the joints for folding.
By these recited improvements I obtain greater range for focusing than. hitherto ;
economy of space, rigidity, a square body throughout thus making the camera
available for lenses of short focus including angle of 90 to 100° of subject on the
plate, as well as narrow angle lenses of long focus for extreme distant objects.
As an illustration of improvements effected-The latest Tourist's Cameras
exhibited say half plate-have a range of focusing power of 12 to 16 inches,
whereas, with my recited improvements as set forth in this Specification I
obtain 24 to 26 inches focusing power, giving thereby greater facility for the
production of Artistic Photographs from Nature also for copying.
Dated this first day of January 1884.

page_text: :
I FREDERIC WILLIAM HART of 8 and 9 Kingsland Green London in the County
of Middlesex Manufacturer of Scientific Apparatus do hereby declare the nature
of my invention for IMPROVEMENTS IN PORTABLE PHOTOGRAPHIC CAMERAS and
in what manner the same are to be performed, to be particularly described and
ascertained in and by the following statements:-—
I first construct the front and back Framework of the Camera body in square or
other rectangular form; for the minimum of Portability it is made the shape of
the largest size plate to be used in the Camera exceeding such dimensions only
by the Framework of dark slide and body necessary to encompass the plate.
Should the plate have a greater dimersion in one direction as a rectangle then,
before the dovetails are glued up two sets of recesses (in square bodies only one sot
is needed) must be formed in the inner surface of both the front and back
framework of body to receive my Improved clamping appliances consisting of
Cam or equivalent Wedge clamps and Folding Disk Heads with screw, pulling,
or half or less turn action the construction and application of which is described
below.
These two sets of clamps one in the shorter dimension as when the plate is usod
on end as usual for Portraits and the other set in the greater dimension as when
the plate is used on its side-Landscape form.
For the Front of the camera body I prefer to use the circular form as shewn in
Fig. 1. for shifting the position of the Lense to cut off more or less foreground.
This is an old and valuable arrangement and for this reason it is briefly described
in the Provisional Specification -The horizontal and vertical slide arrangement
needs not description as that is well know to the more recent makers and users
of Photographic Cameras. The Back can be either Plain, Single or Double swing-
To either form of Front or Back I employ my cam or wedge clamps with or
without screws and folding disk heads for actuating the same.
Having now outlined the general construction of the body-inside the framework
of which is to be placed the usual flexible portion-I now close up the body. The
disk heads not necessarily projecting more than an eigth of an inch, and in
some situations can be flush with the wood work If it be desired to include
in the one package, one or more dark slides or magazine plate holder I place such
at the back of the body to arrive at the depth for the construction of my Improved
base-board, but to simplify the description of my Improved base-board I will take
the body plain with its hinged focusing screen as shewn in Fig. 1 and proceed to
describe my Improvements for obtaining great range of focus combined with
rigidity. I will take the body as folded or shut up and form around it a casing
see Fig. 2 embracing the Top, Front, Bottom and Back which when unfolded gives
the length of the base-board see Fig. 3 Three of these angles being hinged and
the fourth angle secured when surrounding the body-by lock, spring bolt or
hooks. The side on which the hinges are have two separate rabbeted slides
see Fig. 3. A A in these slides are one or more of the usual nuts bb bb for the
screws which fixes the Camera-base to the tripod stand.
In cameras hitherto constructed with folding tailboards the above mentioned.
rabbeted slides are for the sole purpose of locking the hinged joints they only
partly serve this purpose in my improvements but moreover enable me to adjust
the Centre of Gravity of the Camera over the Centre of Support when using a
=

page_text: tripod stand, whether a lense with a focus of three and a half, twenty-four or more
inches is in use.
This is their main purpose, as, in my Improved base-board when unfolded I lock
the hinges on the opposite side, see Fig. 4. C C C and thus obtain the maximum
of rigidity; for this purpose I prefer triangular bolts of steel or bronze Cc.
working on and under metal plates d d flush with the base-board which enables
one to take up wear at any time and thus ensure the continuance of the utmost.
rigidity.
This surface has hitherto been the bottom in which the nut for fixing the
camera to the tripod stand has been inserted, but in my improved form it is the
working top surfaco by which I gain greater rigidity than heretofore.
The camera body frames slide to and fro being kept parallel by the side guides
Fig 4 E in which work the plates G and stirrups HFigs. 5. 6 & 7. of my improved
cam or wedge clamps and screws with folding disk heads.
When it is desired to focus by Rack and Pinion the inside metal strips of these
guide plates have notches at regular intervals and by their sides are ploughed
grooves in Base-board in which slide short lengths of rack say about one sixth
of the length of the base-board, on each short length of rack is a spring with
detent piece to engage in the before mentioned notches the base of the rack is
either rabbeted or half V with corresponding counterparts to slide in and so
prevent falling out; these short lengths of rack are placed in the know position on
the base-board to suit the focus of the lense in use at the time.
The pinions have the folding disk heads so that all shut up close when great
compactness is a desideratum.
I now proceed to describe my improvements in clamping the body and slides
by means of cam or its equivalent plain wedge according to situation, with
screw, pulling or half turn action of the folding disk heads to same.-Fig. 5 shows
a metal plate G connected by rods or wires H to a plate I in a slot of which the
cam K works The action being as follows; the plate G. (one on each side of
body) slides in the side guides E Fig. 4 end view, the wires or rods H pass freely
through holes in the body of the camera, the Plate I comes flat against the inside
of the body and is prevented from having lateral motion by headed pins in the
slots J the cam K being worked by a half turn or less of the disk head on the
outside of the camera lifting the plate I and thus clamping the bottom of the body
and plate G to the side guides E. Second method shewn in Fig. 6. Here the
plates G¹ and stirrups H' slide in the side guides El as above, the wedges K' are
connected by a right and left handed screwed rod J' so that when the disk head X'
is turned the wedges (which move in the recesses cut for them as described above
before the body is glued up) are brought towards each other under the stirrups
and thus firmly clamp the body to the base-board.-Third form Fig. 6 The parts
the same but the wedges follow each other as i i, a plain screwed rod j, and
nuts on front and back of each of the wedges for adjusting the position, and the
wedges simply pulled under the stirrups or the end of the rod is screwed and
works in the spindle of the folding disk heads, such a spindle to be equal to the
length of the wedge, then by turning the disk head the wedges are drawn under
the stirrups by the screw action or again each wedge can be worked independently
on each side of the camera body when the body is not reversible from vertical to
horizontal. Fig 7 shews the cam action and folding disk head as applied to the
Front slides on which the Lense is mounted; L" is the cam N₁ the disk plain
edge or milled, n studs on the same M" the folding half disk pivoted to the
studs no metal stripes or springs on which the cam slides in exerting the .
clamping action on the slide P or Front of the body Q.
Having thus 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
1* The employment of the slides AA Fig 3 for carrying the nuts for the purpose,

page_text: 2nd The locking by adjustable triangular bolts on the opposite side to the hinges
for the purpose as substantially set forth and described.
3d The employment of the side of the baseboard on which the bolts are
as the top working surface for the purpose as substantially set forth and
described.
4th The base board forming a casing entirely round the camera body with
the addition of dark slides or magazine plate holder if desired by which I obtain
the maximum of length without the introduction of weak extending slides as
hitherto used) the combination as substantially set forth and described.
5th The cam wedge and stirrip combined with or without screw action for
clamping the parts as substantially set forth and described.
6th The folding disk head to screws, cams and pinion spindles or axes by the use
of which much less space is occupied in the packing of Photographic Cameras as
substantially set forth and described.
Dated this 30th day of September 1884.