Improvements in or relating to Regulating Shutters for Photographic Cameras.
Year: 1890

page_text: Date of Application, 26th Nov., 1890
Complete Specification Left, 26th Aug., 1891-Accepted, 3rd Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in or relating to Regulating Shutters for
Photographic Cameras.
I, ARTHUR SAMUEL NEWMAN of 71 Farringdon Road, London, in the County
of Middlesex, Electrician, do hereby declare the nature of this invention to be as
follows:
This invention relates to shutters for photographic cameras and consists in
regulating the speed of the movement of the shutter (that is, to regulate the length
of time of exposure) by means of a pneumatic cylinder and piston.
Letters Patent No. 7156 of 1886 were granted to me for an invention in
connection with photographic shutters in which a pneumatic cylinder and piston
are employed for regulating the speed by more or less opening or closing a valve
through which latter air is drawn into or expelled from the cylinder and according
to the regulated size of the opening so is the speed regulated.
Now my present invention is designed to dispense with the said regulating valve
and a tight fitting piston and instead thereof use a valveless cylinder having a
loosely fitting piston working therein.
The piston rod is connected to some working part of the shutter slide or to some
part of the apparatus connected therewith in any suitable or convenient manner
such as in the manner of connecting up the variable expansion gear or valve gear
of a steam engine in which (as is well understood) by moving the regulating gear
the length of travel or movement of the valve upon the steam ports of the engine is
varied, that is in my present invention the length of movement of the piston itself
is thus increased or diminished and thus acts to regulate the speed of the shutter
and so regulate the time of exposure.
For example the piston rod connects upon an arm or crank attached to the
shutter disc the position of the outer end of the piston rod upon such arm or crank
being varied by means of an adjusting lever or by means of a set screw or otherwise
(just as the position of the valve rod is varied in the link of link motion valve gear
for steam engines) thus varying the length of travel of the piston.
Instead of using the above mentioned means of varying the length of travel of
the piston I can obtain similar results by mounting the cylinder on a slide, swivel,
or joint and varying its position with relation to some working part of the shutter.
Dated this 26th day of November 1890.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Regulating Shutters for
Photographic Cameras.
I ARTHUR SAMUEL NEWMAN of 71 Farringdon Road London in the County
of Middlesex Electrician do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement :-
This invention relates to shutters for photographic cameras and consists in
improvements in regulating the speed of the movement of the shutter (that is to
regulate the length of time of exposure) by means of a pneumatic cylinder and

page_text: Letters Patent No. 7156 of 1886 were granted to me for an invention in
connection with photographic shutters in which a pneumatic cylinder and piston
are employed for regulating the speed by more or less opening or closing a valve
through which latter air is drawn into or expelled from the cylinder and according
to the regulated size of the opening so is the speed regulated.
Now my present invention is designed to dispense with the said regulating valve
and tight fitting piston and instead thereof I use a valveless cylinder having a
loosely fitting piston working therein.
The piston rod is connected to some working part of the shutter slide or to some
part of the apparatus connected therewith in any suitable or convenient manner
such as in the manner of connecting up the variable expansion gear or valve gear
of a steam engine in which (as is well understood) by moving the regulating gear
the length of travel or movement of the valve upon the steam ports of the engine is
varied that is in my present invention the length of movement of the piston itself
is thus increased or diminished and thus acts to regulate the speed of the shutter
and so regulate the time of exposure.
For example the piston rod connects upon an arm or crank attached to the
shutter disc the position of the outer end of the piston rod upon such arm or crank
being varied by means of an adjusting lever or by means of a set screw or other-
wise (after the manner in which the position of the valve rod is varied in the link
of link-motion valve gear for steam engines) thus varying the length of travel of
the piston.
Or the piston rod may be permanently connected to the moving part of the
shutter and the regulating effect produced by swinging-or moving the position of-
the valveless cylinder so as thus to vary the length of travel of the piston.
Instead of using the above mentioned means of varying the length of travel of
the piston I can obtain similar results by mounting the cylinder on a slide swivel
or joint and varying its position with relation to some working part of the shutter.
And in order that my present invention may be the more easily understood and
readily carried into practice I will proceed to describe the drawings hereunto
annexed.
Figure 1 illustrates the pneumatic regulating device according to my present
invention and regulating lever in connection therewith in position to allow the
quickest exposure and
Figure 2 shows a similar view to Figure 1 but the regulating lever adjusted so
as to produce the slowest movement.
a is the pneumatic cylinder-b the loosely fitting piston therein.
c is the piston rod the outer end of which is connected to the arm or lever d upon
which arm d it is capable of moving or sliding.
The lever d is fixed to some working part of the shutter (not shown) and turns
upon the axis e while the dotted lines d' show the limit of movement of this arm d.
fis the adjusting lever or regulator which turns on the pin or axis g and the
outer end of this regulator extends outside of the case has shown.
The inner end 2 is connected to the piston rod c by means of the connection i
engaging the loop c¹ or may be otherwise suitably connected so that by moving the
regulator to the extreme left of its movement (as shown in Figure 1) the piston
rod chas practically no movement imparted to it-hence the piston is not moved
and the shutter attached to or in connection with the arm or lever d is not retarded
and is free to travel as fast as it can.
By moving the regulator f' to the extreme right (as shown in Figure 2) the
outer end of the piston rod is moved along the arm d to about the position shown
in Figure 2 and thus when the shutter is released the arm or lever d is caused to
travel up to the position shown in dotted lines at d Figure 2 hence causing the
piston rod c to travel a considerable distance and with it the loosely fitting piston b.

page_text: The air can only obtain access to the underside of the piston 6 by passing between
the piston b and the wall of the cylinder a hence the travel of the piston b in the
cylinder a is very much retarded and the shutter is regulated accordingly.
By placing the regulator handle f¹ in any intermediate position (between the
extremes shown in Figures 1 and 2) the speed of the shutter and hence the length
of exposure can be regulated as desired.
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. The combination of a pneumatic valveless cylinder a piston loosely fitting
therein and a piston rod having the outer end thereof connected to some working
part of a photographic shutter arranged and acting substantially in the manner and
for the purposes hereinbefore set forth.
2. In a device or apparatus for regulating the speed of photographic shutters I
claim a valveless pneumatic cylinder a piston loosely fitting therein and a piston
rod the outer end of which is connected to some working part of the shutter in
combination and in conjunction with a regulating lever connected to said piston rod
or other suitable regulating device or arrangement so that the length of travel of
the piston rod and consequently of the piston may be varied as desired substantially
in the manner and for the purposes hereinbefore set forth.
Dated this 26th day of August 1891.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Patentee.