Improvements in Detective Cameras.
Year: 1893

page_text: Date of Application, 2nd Oct., 1893
Complete Specification Left, 2nd July, 1894-Accepted, 4th Aug., 1894
PROVISIONAL SPECIFICATION.
Improvements in Detective Cameras.
I, JETHRO MARSH, of 49 Aytoun Road, Stockwell London, Engineer, do
hereby declare the nature of this invention to be as follows:-
66
The camera may be of rectangular or other form suitable for the purpose, and is
preferably of small size to permit of its being secreted in the sleeve of the operator,
where it may be secured by a strap passing round the arm or by other suitable means.
A fixed focus or other suitable lens may be used which may be adjustable for near
objects. Any suitable shutter may be used for giving the necessary time or
instantaneous exposures, but that kind known as pneumatic" is very suitable.
The compressible ball is attached to the piston barrel or other device for operating
the shutter, by means of the usual tube. The camera being carried in the sleeve,
the tube extends preferably backward therefrom in the sleeve to a pocket or other
place convenient where it may be squeezed when desired. A stop-cock may be
provided between the ball and the shutter for the purpose of closing communication
except when the exposure is about to be made.
The camera has a magazine at its back which may carry any reasonable number
of plates or films each contained in a carrier, made preferably of thin metal, which
leaves the sensitive surface of the plate or film open, and which has a projection
extending out beyond the said plate or film at one of its edges by which the carrier
and the plate or film it contains may be manipulated as hereinafter described. The
magazine is an extension of the camera and the plate or film carriers are packed
therein face to back. They are pressed toward the lens by a spring, and suitable
Fitted with hinges to
stops or ledges maintain the front plate at the proper focus.
the open side of the magazine there is a light tight loose bag having its mouth over
the projections ou the carriers, of a depth and width at least equal to the length and
width of a carrier. When the plate or älm nearest the lens has been exposed, the
operator taking the closed end of the bag between his finger and thumb grasps the
projection on the carrier containing the exposed film or plate, draws it out from
the front of the magazine into the bag and transfers it to the back, finally pushing
it between the spring and the last carrier whose place it will then occupy,
the carrier containing the unexposed plate or film now nearest the lens, will be
pressed forward to the focus and be ready for exposure, the process of changing
being repeated until all the plates have been exposed. The bag may be detachable
from the magazine for storing the latter with charged carriers, or one of the sides of
the magazine may open for the purpose.
while
Instead of a magazine like that described, I may use a roll holder and operate it
from the front of the camera by any suitable means.
Any suitable view finder may be used. This I attach to one side of the camera
in such a way that it may be slided to or from it, and in a line parallel to the
principal axis of the lens, and I may make it to turn on its sliding support in a
plane at right angles to the principal axis.
When it is desired to use it, the finder is drawn out, (its support sliding in the
suitable guide or guides on the side of the camera,) and held between the fingers of
the operator, then because the support is parallel with the principal axis of the lens,
the camera will be in correct position for making an exposure when the object to be
photographed is seen in the finder. The turning of the finder on its support renders
it more convenient to use.
Dated this Sanand day of Databar 1902

page_text: COMPLETE SPECIFICATION.
Improvements in Detective Cameras.
I, JETHRO MARSH of 4 Wellclose Square, St. George's-in-the-East, but formerly
of 49 Aytoun Road Stockwell, London, 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 :—
The object of this invention is to provide means for taking photographs
unobserved, and if of living objects, without their being aware of it. The camera
may be of rectangular or other form suitable for the purpose, and is preferably of
small size to permit of its being secreted in the sleeve of the operator where it may
be secured by a strap passing round the arm, by fastening it to the sleeve or by
other suitable means. A fixed focus or other suitable lens may be used which may
be adjustable for objects at different distances. Any suitable shutter may be used
for giving the necessary time or instantaneous exposures, but that kind known as
"pneumatic" is very suitable. The compressible ball or its equivalent is attached
to the piston barrel or other device for operating the shutter, by means of the usual
tube. The camera being carried in the sleeve, the tube extends preferably back-
ward therefrom in the sleeve to a pocket or other place convenient where the ball
may be squeezed when an exposure is desired. A stop cock may be provided
between the ball and the shutter for the purpose of closing communication except
when an exposure is about to be made.
If desired the camera may be carried at the back of the arm in the sleeve, the
camera lens being so placed that its principal axis is at right angles to the arm the
rays of light being reflected to the plate by means of a mirror or prism. Or a
similar result may be obtained by placing a mirror or prism in front of the camera
described herein with reference to the accompanying drawings so as to reflect the
rays of light to the camera lens.
The camera has a magazine of any suitable kind at its back. Instead of that
hereinafter described I may use a roll holder and operate it from the front of the
camera by any suitable means. Any suitable view finder may be used. This I
prefer to attach to one side of the camera in such a way that it may be slidden to
or from it in a line parallel to the principal axis of the camera lens, and I may
make it to turn on its sliding support in a plane at right angles to the said
principal axis.
When it is desired to use it, the finder is drawn out (its support sliding in the
suitable guide or guides on the side of the camera,) and held between the fingers of
the operator, then because the support is parallel with the principal axis of the
camera lens the camera will be in an approximately correct position for making an
exposure when the object to be photographed is seen in the finder. The turning of
the finder on its support renders it more convenient to use.
Referring now to the accompanying drawings of which
Fig. 1. represents a longitudinal section of a camera constructed according to this
invention, Fig. 2. a sectional plan of the same,
Fig. 3. a plan showing the arrangement of the finder,
Fig. 4. a back view of the front plate of the camera showing the mechanism for
operating the shutter, and
Fig. 5. a perspective view of the camera.
A
In the drawings the back part or magazine B, of the camera A, is shown
rectangular corresponding to the shape of the plates C, to be used, while the front
is of partly elliptical section to conform to the shape of the cuff or sleeve.
strap D, serves to secure the camera to the arm of the operator. The lens E, is
placed close behind the shutter F, which oscillates between it and the opening a in
the front plate of the camera. The shutter F, consists of a segmental piece of
metal or other material and is capable of oscillation about a centre pin 6. It is
actuated by a spring arm c part of which rests on an expansible bag d of india-

page_text: rubber, caoutchouc or other suitable material, which has its open end secured to.
one end of a tube e in communication with the compressible ball by means of the
flexible tube 9. A second shutter is provided, which also oscillates about the-
centre b, for the purpose of closing the opening in the shutter F when this latter
returns to its normal position. The shutter h is connected to the lever c by the-
link which works on a pin carried by a crank arm of the shutter h, the pini
extending from the shutter through a slot k in the shutter F. This shutter does.
not move until the pin reaches one end of the slot k which is so placed that the
hole always opens when the bag d is being distended, but is covered by the
shutter when it collapses. The stroke of the shutter F, is limited by a bar m
carried by a spindle which projects to the outside of the camera and there carries
a knob n. A pinch cock o is shown on the tube g near the ball to prevent.
accidental exposures.
The magazine B, is of a kind already well known, the plates C are carried in
sheaths provided with projecting pieces p by which the plates may be transferred
from the front to the back of the magazine B. A spring g keeps them all
pressed towards the front, and to enable them to be changed, a light tight bag -
is provided into which the sheaths and plates C are drawn, the projections p
being gripped in the closed end of the bag r between the finger and thumb of
the operator.
The camera is furnished with a finder G movable to and from the camera in
a direction parallel to the principal axis of the camera lens by means of a
slide H working in guides J. The finder G may be carried at the front end
of this slide on the pin s, but I have shown it carried on the centre t by a
liuk K which is carried on the bar by the pin s.
The finder G is rotatable on.
the pins and the link K also rotatable about the pin t.
The mode of operation is as follows:-The operator having selected the object
to be photographed draws out the finder G which is guided in its travel by the
slide H working in the guides J, until the finder is in a position convenient for
holding between the fingers, or between the finger and thumb, he then proceeds
to get an image of the object in the finder by moving that arm to which the
camera is attached. If he desires an instantaneous exposure he turns the knob n
until the bar m is out of the line of travel of the shutter F. so as to allow a
full stroke, opens the cock o and squeezes the ball f with his free hand, causing
air pressure to be transmitted along the tube g to the bag d which is thereby
expanded. The spring arm c resting on the bag d by means of the link j first.
causes the shutter and next the shutter F to move, so that the hole in the
latter will rapidly pass the opening a in the front plate of the camera. When.
the air pressure is released in the bag d the spring arm c by means of the link)
will return the shutters to their former position acting first on the shutter h,.
causing it to close the opening and keep it closed during the whole of the
return stroke as herein before described. If the operator desires a time exposure
he turns the knob n till the bar m is in the position shown in Figure 4, then when
the ball is pressed the shutters will be moved until the hole in the shutter F
coincides with the hole a in the camera front in which position they will remain
until the air in the bag d is released. The first plate C having been exposed is.
transferred to the back of the magazine B by the operator who with the extreme
end of the flexible light tight flexible bag r between his finger and thumb grasps
the projection P on the sheath carrying the exposed plate, draws it out of the
magazine into the bag r and pushes it between the last of the series of plates C and
the spring
By this operation another plate is pressed forward ready for
exposure.
for the purpose of filling and emptying the magazine the changing
bagr is made removable, in the drawings it is shown as having a rim fitting tightly
over the mouth of the magazine. The front plate of the camera is shown hinged
and may be secured to the camera body by a catch or other device.
rrangement an inspection of the shutter mechanism and lens may be easily
made.
By this

page_text: 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. A photographic camera adapted to be carried in the sleeve of the operator
and there used for the purpose of taking photographic negatives or pictures.
2nd. In a photographic camera adapted to be carried and used in the sleeve of
the operator, a finder adapted to slide to and from the camera in a direction parallel
to the principal axis of the camera lens and rotatable in a plane at right angles to
the said principal axis.
3rd. In a photographic camera adapted to be carried and used in the sleeve of
the operator, the combination of a finder adapted to slide to and from the camera
in a direction parallel to the principal axis of the camera lens and rotatable in a
plane at right angles to the said principal axis, with a magazine in which the plates
or films are changed by transferring them from the front to the back in a light tight
bag, and a pneumatic shutter actuated by means of a ball and tube substantially as
and for the purpose described.
Dated this 2nd day of July 1894
JETHRO MARSH.