Improvements in Shutters for Photographic Cameras.
Year: 1890

page_text: Date of Application, 29th Nov., 1890
Complete Specification Left, 31st Aug., 1891-Accepted, 3rd Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
We ARTHUR SAMUEL NEWMAN of 71 Farringdon Road London in the
County of Middlesex Electrician and ARTHUR LEWIS ADAMS of 81 Aldersgate
Street in the City of London Manufacturer of Photographic Apparatus do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in shutters for photographic cameras
more especially for what are known as "detective" or hand cameras and is
designed to produce a shutter which is simple in construction and action and which
after each exposure will return to its normal position for giving the next exposure
without admitting any light whilst so returning.
This improved shutter is so arranged and constructed that by pressing the release
knob or projection the power necessary to work the shutter is provided immediately
before releasing said shutter to make the exposure.
The arrangement and construction is as follows:-
A thin plate of metal or other suitable opaque substance of a quadrant shape or
similar sector of a circle shape is mounted to turn on a pin at or at about its centre
so that its path of travel lies across the lens aperture.
This plate or shutter has a suitable opening or slot cut or formed therein.
A second plate or auxiliary shutter of similar shape and having a similar slot or
opening therein is mounted in a similar manner to the first named plate its travel
being across the lens in the same way as the first shutter the two shutters moving
in parallel planes.
The auxiliary shutter is pushed in one direction by a rod or similar appliance
having a knob or projection which extends outside the camera case and is brought
back to its normal position by a main actuating spring such as a coiled spring or
other suitable appliance. On one part of this auxiliary shutter there is a cam or
other surface (to act as hereinafter described) and on another part there is a recess
or projection to engage a catch which catch holds the auxiliary shutter "open
until the shutter proper releases this catch and the auxiliary shutter is at once
returned to its normal position carrying with it the shutter proper.
"
The first plate or shutter proper is mounted at its centre on the same pin or axis
as the auxiliary shutter to which latter it is connected by a coiled spring so that
when the auxiliary shutter is moved the shutter proper tries to follow but is
prevented by a catch which retains it in the normal position until the opening or
slot in the auxiliary shutter is coincident with the lens aperture whereupon the
aforesaid cam surface or projection on the auxiliary shutter releases the said catch
and the shutter proper then travels across the lens aperture and so gives the
exposure and thereafter releases the catch which engages the auxiliary shutter and
the two shutter together are then drawn back (by the main actuating spring) in
such a manner that no light is admitted while so returning.
The speed of the shutter (i.e. the length of time of the exposure) may be
regulated by any suitable or convenient regulating device or appliance as for
instance by a pneumatic cylinder and piston or by a leather or other suitable
brake etc.
"
A second notch recess or projection on the shutter proper engages the same
catch as the first notch or recess on same engages and so holds the shutter "open
for any length of time until the auxiliary shutter is again moved and by the cam
surface or projection thereon cause the said catch to release the shutter proper and

page_text: so close the lens. Thus it will be seen that any exposure can be given from
instantaneous to any desired length of time.
Dated this 29th day of November 1890.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Patentees.
Figure 1 shows a front elevation of a photographic shutter arranged and
constructed in accordance with our invention when the parts are at rest.
Figure 2 shows a corresponding view of the same parts just before an exposure
takes place.
Figure 3 is a back view and Figures 4 and 5 edge views of the same.
Figure 6 is a vertical section (on a larger scale) of the lens holder taken through
the line 1-1 Figure 3 and
Figures 7, 8, and 9 show separate views of some of the parts.
Corresponding letters of reference apply to corresponding parts in all the
figures.
Our improved shutter is so arranged and constructed that by pressing the release
knob or projection a the power necessary to work the shutter is provided
immediately before releasing said shutter to make the exposure.
The arrangement and construction of the apparatus is as follows:-
A thin plate of metal or other suitable opaque substance of a quadrant shape
or similar sector of a circle shape or equivalent is mounted to turn on a pin bat or
about its centre so that its path of travel lies across the lens aperture.
t
This plate or shutter has a suitable opening or slot 6 cut or formed therein.
A second plate or shutter having a slot or opening c¹ therein is mounted on the
pin in a similar manner to the plate 6 its travel also being across the lens in the
same way as the shutter the two shutters moving in parallel planes.
The shutter b is pushed in one direction by a rod a or similar appliance having a
knob or projection which extends outside the case and is brought back to its
normal position by a main actuating spring such as a coiled spring a¹ or other suitable
appliance.
On one part of the shutter b there is a cam or other surface 63 (to act as herein-
after described) and on part of the plate or shutter c there is a recess or projection c³
to engage a catch c³ which catch c³ holds the plate or shutter c until the cam
surface on the shutter releases the catch c³ and the plate or shutter c is at once

page_text: released and travels across the lens aperture to the position indicated in dotted
lines in Figure 2 and the opening c¹ thus gives the desired exposure and thereafter
the two shutters then return to their normal position as in Figure 1.
As the two shutters b and c return together-in the opposite direction to the
arrows in Figure 2-across the lens aperture no light is admitted to such lens
aperture the shutter b carrying with it the shutter c on the return movement.
The plate or shutter b is mounted at its centre on the same pin or axis 6' as the
plate or shutter c to which latter it is connected by a coiled spring e so that when
the shutter bis moved by the rod a the spring e is wound up and the shutter c tries
to follow but is prevented by the catch which retains it in the normal position
until the opening 62 in the shutter b is coincident with the lens aperture whereupon
the aforesaid cam surface or projection 63 on the shutter releases the said catch c³
and the shutter c actuated by the spring e then travels across the lens aperture and
so gives the exposure and thereafter on releasing the pressure on rod a the two
shutters are then automatically drawn back (by the main actuating spring a') in
such a manner that no light is admitted while so returning.
The speed of the shutter (i.e. the length of the time of exposure) may be
regulated by any suitable or convenient regulating device or appliance as for
instance by a pneumatic cylinder and piston (such as the invention set forth in
Newman's application for Patent No. 192740) or by a leather or other suitable
brake et cetera.
A second notch recess or projection c* on the shutter c engages the same catch c³
as the first notch or recess e² on same engages and so holds the shutter open for any
length of time until the shutter b is again moved by further pressure on the rod a
and the cam surface or projection 63 causes the said catch c³ to release the shutter c
and so close the lens. Thus it will be seen that any exposure can be given from
instantaneous to any desired length of time.
A separate spring a fixed on the pin or screw x¹ (see Figures 1 and 2 may be
added to retain the double shutter) in the "open" position as long as desired by
engaging a projection such as a² on the shutter b see Figure 7.
This spring a being disengaged or dislodged so as to allow 6 to return-by any
suitable means such as a cam surface on c or a separate push bar (not shown) which
would extend outside the case for this purpose-but as to this spring & we make no
claim.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what
we claim is :--
In shutters for photographic cameras the combination of the shutters or plates 6
and c rod a connected directly to the shutter 6 to force same across the lens
aperture and the spring e wound up by the movement of shutter to actuate the
shutter c and the main spring a¹ to automatically return the parts b and c to their
normal position all arranged combined and acting substantially in the manner and
for the purposes hereinbefore described and illustrated in the drawings hereunto
annexed.
с
Dated this 31st day of Sentember 1891
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Patentees.