Improvements in Apparatus for Regulating the Speed of Photographic Shutters.
Year: 1892

page_text: Date of Application, 15th Nov., 1892
Complete Specification Left, 15th Aug., 1893-Accepted, 7th Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Regulating the Speed of
Photographic Shutters.
We, ARTHUR SAMUEL NEWMAN and JULIO GUARDIA, trading as Newman
& Guardia of 71 Farringdon Road, London, Manufacturers of Photographic
Apparatus, do hereby declare the nature of this invention to be as follows:-
:―
This invention relates to improvements in apparatus or means for pneumatically
regulating the speed of travel of photographic shutters.
Letters Patent No. 7156 of 1886 were granted to the aforesaid Arthur Samuel
Newman in respect of his invention of the pneumatic regulation of the speed of
photographic shutters and in the particular apparatus therein illustrated as well as
in other apparatus which we have since tried there have always been certain of the
parts of such regulating device open or uncovered and therefore accessible to grit
and dust or the like which naturally has been found to interfere with the fine
adjustment and correct regulation whenever such foreign substance got into the
working parts.
Now according to our present improvements we have devised means to exclude
all sand grit or the like from getting into the working parts of the pneumatic
regulating device and our said present invention is as follows:-
-
We use a pneumatic cylinder mounted rigidly on some part of the photographic
apparatus or such cylinder may be mounted as to be capable of oscillating or moving
or of being moved.
This cylinder we close at both ends tightly and the piston rod passes through a
gland or tight packing if necessary (as in the cylinder covers of reciprocating steam
engines) or a simple close fit of the aperture in the cylinder end around the said
piston rod will usually be found to answer all practical requirements.
This piston rod is connected up to or is in connection with some working part of
any suitable photographic shutter or equivalent device for giving photographic
exposures.
For the sake of accuracy of working we find it advantageous to form the piston
of rather great length and connect same up to the piston rod by a universal joint or
the like for instance the headed end of the piston rod enters a slot which passes said
head into a hollow formed in the piston while the rod is thus flexibly connected to
the piston and can be moved round in all directions.
Now the most essential feature in our present invention consists in the
arranging and mounting of a second and distinct chamber alongside or in proximity
to the aforesaid cylinder with which it acts in combination and in conjunction as
follows:-
:-
A passage (or passages) is made from each end or near each end of the aforesaid
air cylinder into the said air chamber thus making a clear course (or a kind of
by-pass") for the air from one side of the piston to pass round (via the air
chamber) to the opposite side of the piston and by interposing a regulating valve
(or valves) or choking device in some part of the said air chamber or passages
leading thereto we can thus vary the size of the aperture through which the
air has to pass or completely shut off said aperture so that the speed of travel
of the piston is thus regulated as desired and thus the speed of the shutter is
regulated.
For this purpose we have found the following to be a very advantageous way to
regulate:-
We bore out the air chamber from one end only and at the far end we form a

page_text: a screw plug may be screwed up or unscrewed the said plug or valve fitting tightly
into the bored end of the air chamber and thus closing same while its inner part or
valve stem is of a less size than the diameter of the bere of said air chamber and
the inner end of said valve stem is coned to fit down onto the aforesaid coned seating
towards and away from which same may be moved by screwing or if desired by
other suitable means.
In place of air acting as the retarding medium in such apparatus we may if
desired use a suitable liquid therein as the whole apparatus being closed in (as
before described) such liquid could not escape.
Dated this 15th day of November 1892
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Regulating the Speed of
Photographic Shutters.
We, ARTHUR SAMUEL NEWMAN and JULIO GUARDIA, trading as Newman
& Guardia of 71 Farringdon Road, London, Manufacturers of Photographic
Apparatus, 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 relates to improvements in apparatus or means for regulating the
speed of travel of photographic shutters by a pneumatic retarding device or
equivalent "dash-pot" or "cataract" retarding device.
Letters Patent No. 7156 of 1886 were granted to the aforesaid Arthur Samuel
Newman in respect of his invention of the pneumatic regulation of the speed of
photographic shutters and in the particular apparatus therein illustrated as well as
in other apparatus which we have since tried there have always been certain of the
parts of such regulating device. open or uncovered and therefore accessible to grit
and dust or the like which naturally has in some cases been found to interfere with
the fine adjustment and correct regulation whenever such foreign substance got into
the working parts.
Now according to our present improvements we have devised means to exclude or
obviate the likelihood of any dust sand grit or the like from getting into the
working parts of the pneumatic regulating device and our said present invention is
as follows:-
We use a pneumatic cylinder mounted rigidly on some part of the photographic
apparatus or such cylinder and adjuncts thereof may be mounted as to be capable of
oscillating or moving or of being moved.
This cylinder we close at both ends tightly and the piston rod passes through an
aperture in one or both ends which aperture may have a gland or tight packing if
necessary (as in the cylinder covers of reciprocating steam engines) or a simple
close fit of the aperture in the cylinder end around the said piston rod will usually
be found to answer all practical requirements.
This piston rod is connected up to or is in connection with some working part of
any suitable photographic shutter or equivalent device for giving photographic
exposures.
For the sake of accuracy of working we find it advantageous to form the
piston or plunger of rather great length and connect same up to the piston rod
by a universal joint or the like for instance the headed end of the piston rod
enters a slot which allows said head to pass into a hollow formed in the piston while
the rod is thus flexibly connected to the piston and can be moved round in all
directions.

page_text: Now the most essential feature in our present invention consists in the arranging
and mounting of a second and distinct chamber or passage alongside or in proximity
to the aforesaid cylinder with which it acts in combination and in conjunction as
follows:-
A passage (or passages) is made, from each end or near each end of the aforesaid
air cylinder into the said air chamber thus making a clear course (or a kind of
by-puss") for the air from one side of the piston to pass round (via the air
chamber or equivalent such as a pipe or passage) to the opposite side of the piston
and by interposing a regulating valve (or valves) or choking device in some
part of the said air chamber or the like or passages leading thereto we can thus
vary the size of the aperture through which the air has to pass or completely
shut off said aperture so that the speed of travel of the piston is retarded to
any degree and thus regulated as desired and thus the speed of the shutter is
regulated.
For this purpose we have found the following to be a very advantageous way to
carry out this part of our present invention:—
We bore out the air chamber from one end only and at the far end we form a
contracted conical shaped ledge to act as a valve seating towards or against which
a screw plug may be screwed up or unscrewed the said plug or valve fitting tightly
into the bored end of the air chamber and thus closing same while its inner part or
valve stem is of a less size than the diameter of the bore of said air chamber and
the inuer end of said valve stem is coned to fit down onto the aforesaid coned
seating towards and away from which same may be moved by screwing or if desired
by other suitable means.
In place of air acting as the retarding medium in such apparatus we may if desired
use a suitable liquid therein as the whole apparatus being closed in (as before
described) such liquid would not escape.
It will thus be seen and easily understood that the air (or liquid) enclosed in
this retarding device practically remains unchanged merely passing backwards
and forwards (through the "by-pass ") from one side of the piston or plunger to
the other and not (as heretofore usual) drawing in a fresh supply of air at such
operation.
And in order to further explain this invention we have hereunto annexed a sheet
of drawings in which :-
Fig. 1 is a sectional view taken longitudinally through a pneumatic cylinder
having our present improvements applied thereto.
Fig. 2 is same view as Fig. 1-with the regulating device shown tightly
closed.
a is cylinder.
b piston.
cis piston rod which is connected up to some working part of the shutter or
shutter mechanism in
any suitable way.
d is passage from a leading from or into air chamber e.
fis second passage between chamber e and cylinder a.
gis screw plug or regulating valve stem.
is handle or lever to revolve same by, or the valve stem g may be operated in
any other suitable manner.
The operation is as follows:-
On the piston 6 Fig. 1 being moved up-the air from the top side of 6 can only
readily escape through the top passage d'air chamber e and lower passage f to the
underside of 6 thus filling the space under as it rises.
Now by more or less choking some part of the passage way or "by-pass" formed
by d and e it is obvious a greater or less resistance is offered to the escape of air
from the side of the piston where the air is being compressed while on the other
hand the partial vacuum created on the opposite side of said niston will further

page_text: mounted at any suitable point but by way of illustration we have shown the coned
end of the spindle g acting as such regulating valve against the coned seating in the
top passage d.
The air or other contents of the cylinder a and by-pass or passage such as de
therefore does not change at each operation of the regulating device but simply
passes round backward and forward from one side of the piston to the other-the
same air being thus used over and over again and similarly with liquid if the latter
or equivalent be used instead of air.
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
1. In apparatus for regulating the duration of photographic exposures-the com-
bination with a closed pneumatic cylinder having a piston or plunger therein of a
passage pipe or secondary air chamber in communication with both ends of said
cylinder and forming a continuous passage so that the air forced out by the upper
side of the piston passes round to the underside of said piston (and vice versa) by
way of said passage way or secondary air chamber and a valve or means to close or
partially close said passage way or secondary air chamber at any suitable point or
points substantially in the manner and for the purposes herein before described and
illustrated by way of example in the drawings hereunto annexed.
2. We claim an apparatus for regulating the speed of photographic shutters
consisting of the combination of a cylinder, a piston or plunger in said cylinder, a
piston rod passing out through a gland or closely fitting aperture in said cylinder
end, a passage way leading from or into said cylinder towards one end thereof a
second passage way leading from or into said cylinder towards the other end thereof
a secondary air chamber interposed between said passages, or said passages may be
otherwise suitably joined, in either case forming a continuous passage pipe or
by-pass" outside of said cylinder from one end of the latter to the other and a
valve or means to cut off or partially cut off said passage substantially in the manner
and for the purposes herein before set forth.
66
Dated this 15th day of August 1893.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.