Year: 1887

page_text: Date of Application, 15th Feb., 1887
Complete Left, 15th Nov., 1887
Complete Accepted, 16th Dec., 1887
I EDGAR THEODORE PERKEN of 14 Canterbury Road Brixton in the County of
Surrey Optician do hereby declare the nature of this invention to be as follows:-
This invention has for its object improvements in the mechanism employed for
actuating shutters used for giving exposure to light of the sensitive film or paper used
in photographic cameras and is designed to make such shutters and their actuating
mechanism more compact and reduced in size so as to be adapted for use either
between the lenses or in front as may be desired and also to regulate the time or
duration of the exposure to be given.
The apparatus is constructed as follows:-
At one corner of the lower part of the apparatus is arranged a coiled spiral spring
one end of which is attached to a barrel which is hereinafter described and the other
end to a peculiar shaped piece of metal (or other suitable material) mounted on an axis
centrally with said spring and having one end or part projecting beyond the exterior
of the frame of the apparatus and forming the handle or catch for loading. On this
piece of metal at a suitable distance from its axis is pivoted a lever which again
works a cross arm fixed to an intermediate arm on the shutter at one end and to the
frame at the other. Thus when the piece of metal having the spring attached is turned
on its axis half a revolution or thereabouts it causes (by means of the lever and cross
arm) the shutter to rise and fall and is then held in position preparatory to letting off
by a lever arm which takes into a catch or notch cut on its side-there is also a second
catch or notch formed on it to catch on to a second lever arm when the shutter is
raised (and so hold it there for fucusing &c.) These two lever arms are arranged
parallel to each other (or thereabouts) and are both hinged to a rocking piece on either
side of its axis so that when the piece is rocked by the releasing action of a pneumatic
piston or by hand one arm is pushed forward and the other drawn back and "vice versa
their motions being in opposite directions to one another.
22
The extent of the rocking action is controlled by an adjustable stop-piece which
when giving an exposure either allows the second lever arm to catch and retain
the shutter (when in the raised position) as long as may be required, or not, as
docinad

page_text: There is also another stop which retains the shutter in the raised position for
focusing &c without using the before mentioned pneumatic apparatus which is of the
ordinary kind for releasing the shutter except that I employ a small piece of very soft
leather fixed through its centre on the under-side of the valve or piston ordinarily used,
this leather being rather larger in diameter than the cylinder in which it works and
is inverted cup-shaped so that the pressure of air causes it to spread out and make a
tight joint or packing without much friction.
The before mentioned spring barrel is arranged with an external catch thereon and
rack so that if it is desired to increase the rapidity of the shutter the barrel can be
moved round and so wind up and tighten the spring by means of said catch which
takes into one of the teeth or indentations in the rack and is retained in the required
position thus strengthening the action of the spring and causing more rapid action of
the shutter.
The various parts can be made of thin sheet metal and can be modified in various
ways without departing from the principle of my invention.
TONGUE & BIRKBECK,
34, Southampton Buildings, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
EDGAR THEODORE PERKEN of 14 Canterbury Road Brixton in the County of
Surrey Optician 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 has for its object improvements in shutters used for giving exposure
to light of the sensitive film or paper used in photographic cameras and is designed to
make such shutters and their actuating mechanism more compact and reduced in size
So as to be adapted for use either between the lenses or in front as may be
desired and also to regulate the time or duration of the exposure to be given.
And in order that my invention may be the more easily understood and readily carried
into practice I will proceed to describe the same with reference to the accompanying
drawinra
Figure 1 is an external front view in elevation of my improved shutter for use in
front of the lenses.
Figure 2 is a view in elevation of the reverse side with back plate removed and
showing the relative position of the parts of the mechanism when "loaded" ready to
give an exposure.

page_text: Figure 3 is same view showing the position after the trigger a has been released
and the shutter raised in which position it is held by the second arm or catch a² on the
trigger a.
Figure 4 is same view as Figures 2 and 3 showing the position of the parts when the
shutter is in its normal condition.
At one corner of the lower part of the apparatus frame is arranged a coiled spiral
spring one end of which is attached to a barrel y which is hereinafter described and
the other end to a peculiar shaped piece of metal (or other suitable material) b
mounted on an axis c centrally with said spring and having an end or part 6¹ projecting
beyond the exterior of the frame of the apparatus and forming the handle or catch
for "loading." On this piece of metal at a suitable distance from its axis is
pivoted a lever d which again works a cross arm e jointed at e¹ to an intermediate
arın on the shutter y at one end and to the frame at the other e².
Thus when the piece of metal 6 having the spring attached is turned on its axis c
half a revolution or thereabouts from the position shown in Figure 4 to the position
shown in Figure 2 it causes (by means of the levers d e and f) the shutter g to rise
and fall and is then held in position (preparatory to letting off) by the lever arm a
on the trigger a which takes into a catch or notch cut in its side and forming the
shoulder. There is also a second catch or notch 63 formed on it to catch on to the
second lever arm a² when the shutter is raised. These two lever arms a¹ and a² are
arranged parallel to each other (or therabouts) and are both pivoted to the trigger or
rocking piece a on either side of its axis a* so that when this piece a is rocked by
the action of a pneumatic piston in the cylinder h or by hand as hereinafter explained
the arm a is pushed forward and then drawn back while the arm a¹ is first drawn back
out of the notch 62 and then pushed forward their motions being in opposite directions
to one another.
Pneumatic action is well known and understood for the purpose of releasing
photographic shutters so that I need only briefly describe the application thereof to suit
my present character of shutter apparatus.
The piston in the cylinder is normally kept pressed down by a small spiral spring
inserted in the top part of the cylinder above the piston upon which latter two small
pins h h project through a slot h* cut in the side of the cylinder and between them
the arm a of the trigger a projects and is thereby moved up and down as before
described.
The trigger a can also be released by hand direct if desired by means of the projection a³
extending below the frame for that purpose.
The extent of the rocking action is controlled by an adjustable stop piece by
moving the knob of which before giving an exposure from the position Figure 4 out
to the position Figure 2 allows the second lever arm a² to catch in the second notch b³
and so hold the shutter up in the position shown in Figure 3 as long as the pressure is
kept up in the cylinder h.
There is also another stop or catch pivoted at m which by catching in the notch b+
retains the shutter g in the raised position (Figure 3) for focussing etc. without using
the before mentioned pneumatic apparatus which latter is of the ordinary kind for
releasing the shutter as previously described except that I employ a small piece of
very soft leather fixed through its centre on the underside of the valve or piston
ordinarily used this leather being rather larger in diameter than the cylinder in which
it works and is of an inverted cup shape so that the pressure of air causes it to
spread out and makes a tight joint or packing without much friction.
"
The before mentioned spring barrel y is arranged with an external catch thereon
and rack so that if it is desired to increase or diminish the rapidity of the shutter the
barrel can be moved round and so wind up and tighten or unwind and slacken the
spring by means of said catch v which takes into one of the teeth or indentations in
the rack and is retained in the required position thus strengthening the action of
the spring and causing more rapid action (or vice versa) of the shutter.
The various parts can be made of thin sheet metal or other suitable material

page_text: and can be modified in various ways without departing from the principle of my
present invention.
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 shutters for photographic cameras the trigger or part a and its connec-
tions a' a² a³ and a acting in conjunction with the spring actuated piece having the
projection and notches 62 63 and 64 cut or formed therein substantially as and for the
purposes hereinbefore described and represented in the drawings annexed.
2. In shutters for photographic cameras the spring actuated piece by which the
shutter is raised and lowered through the medium of the intermediate arms or
levers d'e and substantially as hereinbefore described and represented in the drawings
annexed.
3. The improved arrangement construction and combination of the several parts of
the mechanism for operating shutters for photographic cameras substantially in the
manner and for the several purposes hereinbefore described and represented in the
drawings hereunto annexed.