Improvements in Apparatus for Regulating Photographic Shutters.
Year: 1892

page_text: Date of Application, 28th June, 1892
Complete Specification Left, 21st Mar., 1996-Accepted, 1st Apr, 13:3
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Regulating Photographic Shutters.
We, HENRY HILL of 20, Tradescant Road, South Lambeth Road, London,
Manufacturer of Electrical, Optical and Mechanical Apparatus, and ARTHUR
LEWIS ADAMS of 81, Aldersgate Street, London, Manufacturer of Photographic
Apparatus, do hereby declare the nature of this invention to be as follows :—
This invention relates to apparatus for pneumatically regulating the speed or
travel of shutters for photographic purposes and consists of a pneumatic regulating
device which can be readily adjusted or altered so as to give longer or shorter
exposure as desired.
The pneumatic regulating apparatus according to this invention consists of an air
chamber capable of having its internal area increased or diminished as desired by
means of an adjusting device secured or affixed to that end or part of the apparatus
which is away from or detached from any working part of the shutter while
another part of this air chamber is permanently attached to some working part of
the shutter so that the leverage between it (the air chamber) and the spring
actuating the shutter is never varied the regulation being obtained according to this
invention by varying the size of this air chamber-and this may be done in either
of the following manners :-
1st. A tube (either cylindrical or of other suitable form) closed at one end and
open at the other is permanently connected at its closed end to some working part
of the shutter while its other and open end slides over (or if desired slides into)
another tube of corresponding form and length (or the length may vary) which
it closely fits the one working within the other after the manner of a plunger.
The outer end of this second tube is closed likewise and has connected to it a
crank arm (like a bell crank) turning on a pivot-the free end of this arm acting
as a handle by which to move same and a dial or index plate may be mounted
in combination with the same so as to show exactly the speed at which the shutter
is set.
Thus by moving this regulating handle to its extreme limit on one side or in
one direction the second tube is drawn out of the first and thereby the internal area
of the combined tubes is greatly increased-thus allowing the shutter to work with
more freedom and consequently greater speed.
By moving the index handle to the opposite extreme the one part of the air
chamber is moved closer into the other part and consequently the area of said air
chamber is reduced and when the one part or tube is drawn off the other by the
movement of the shutter the air is more attenuated and consequently the speed of
the shutter is greatly retarded—while at intermediate positions of this index handle
or regulating arm (between the two said extreme points) intermediate speeds are
obtained.
In place of this crank arm for altering the positions of these tubes one upon the
other (i.c. altering the internal area of this air chamber) as hereinbefore described-
other equivalent mechanical means may be used for doing this: for instance, a slide
moving in a line parallel or thereabout with the axial line (ie. the length) of the
air chamber and having a dial or index as before to show the speeds or other
equivalent mechanical devices may be readily applied in order to draw the one tube
off the other or out of the other so as to vary the internal capacity of said air
chamber as and for the purposes hereinbefore described.
2nd. A tube of cylindrical or other suitable shape and open at each end may be
pivotted or mounted so as to be capable of swinging at about the centre of its
length and the moving part of the shutter has a tube or cap (corresponding in

page_text: shape) attached thereto to slide over (or slide into) this pivotted tube at one end
thereof while at the other end thereof another tube or cap of corresponding shape
may be mounted or arranged to slide over (or slide into) this said pivotted tube-
this third tube being drawn in or out by means of a slide, bell, crank lever or other
suitable device so as to vary the internal area of the air chamber thus formed as
before described-cach of these two slide tubes or caps being closed at their outer
end as before the only difference from the first arrangement being that the air
chamber is formed in three parts instead of two.
3rd. In place of having tubes or the like devices sliding upon one another (as
previously described) a regulating action can be obtained by a bellows or the like
arrangement one side or part of the bellows being connected to some working part
of the shutter and another side or part of the bellows connected to a device as before
for varying the position of same so that the internal area of the air chamber in said
bellows is increased or diminished.
Thus the air chamber is compressed or extended or both (when the shutter
is nctunted) in any of the three above described manners or in any mechanically
equivalent manner and the speed of the shutter can be thus regulated in a very
simple manner and without in any way varying the leverage between the air
chamber and the operating spring.
The index handle or regulating arm, slide, or lever by which the internal area of
the air chamber is varied can be held in position by set screw or clamp or in any
other suitable manner-as desired.
Dated this 28th day of June 1892.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Regulating Photographic Shutters.
We, HENRY HILL formerly of 20 Tradescant Road, South Lambeth Road,
London, but now of 151 Fentiman Road, Clapham, London, S.W. Manufacturer
of Electrical, Optical and Mechanical Apparatus and ARTHUR LEWIS ADAMS of
81 Aldersgate Street, London, Manufacturer and dealer 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 apparatus for pneumatically regulating the speed of
shutters (i.e. for regulating the duration of the exposure) for photographic pur-
poses and consists of a pneumatic regulating device which can be readily altered
or adjusted in a novel manner so as to give longer or shorter exposure as desired.
The pneumatic regulating apparatus according to this invention consists of an
air chamber (such as a piston and cylinder or two cylinders working one within the
other) capable of having its internal area or effective part thereof increased or
diminished as desired by means of an adjusting device secured or affixed to that
end or part of the apparatus which is away from or detached from any working
part of the shuter while another part of this air chambar is permanently attached
or connected to some working part of the shutter so that neither the leverage
between it (the air chamber retanding device, and the spring actuating the shutter
is varied, nor is a variable orifice used-both these latter methods being already
known the regulation being obtained according to this invention by varying the
size of the air chamber or effective part thereof acting as a brake and this may be
done in a variety of ways.
The alteration of the size or internal capacity of the air chamber or effective
part may be effected by constructing such air chamber as a piston and cylinder, or

page_text: as a hollow piston or tube closed at one end working as a plunger in a cylinder
or second tube also closed at one end the part working as the piston or plunger
being attached or connected in any suitable manner to some working part of the
shutter mechanism and the second part (rz. the cylinder or cap) being so arranged
1
from the
and mounted that it c
said piston or plunger and set or fixed in any desired position (or the said parts
may be arranged rice versa) so that when the shutter is operated the one part of
the air brake (whether it be the piston or plunger part-or the cylinder or cap or
outermost part) which is permanently attached or connected to some working part
of the said shutter mechanism is always caused to travel exactly the same distance
that is its travel or movement is constant while the variable regulation is obtained
by sliding or moving the other part upon or in the said part connected to the
shutter and thus vary the resistance offered by the air by thus altering the con-
ditions under which the air is compressed or attenuated (or both) as the case may
be to act as a brake of greater or less resistance to regulate the duration of
exposure.
And in order that this invention may be fully understood and readily carried
into practice we will proceed to describe same with reference to the accompanying
drawings which illustrate several different methods of regulating photographic
shutters according to this invention.
DESCRIPTION OF THE DRAWINGS.
Figs. 1 and 2 illustrate a cylinder a connected to a working part (i.e. a crank
arm) of a photographic shutter (the latter is not shown) with a more or less
closely fitting piston or plunger e capable of being easily slid or moved in and out of
said cylinder a by a device consisting of a lever fixed on the pivotted arm e
pivotted at the free end e of this pivotted arme extending through the camera case
or shutter frame etc. g.
A dial or index is advantageously mounted on the exterior of g to show the
speeds for which the shutter can be regulated.
For facility of description we may hereinafter refer to that part of the pneumatic
device which is permanently attached to some working part of the shutter o
shutter incchanism as the "attached part" while the other part by moving which
< non-attached'
the regulation is effected may be hereinafter referred to as the
part.
Fig. 1 shows the arm e e* moved to the extreme right so that the internal are
or capacity of the air chamber is of the largest and consequently when the shutter
is operated the cylinder a in moving from the position shown in full lines to that
shown in dotted lines in the same figure will have the least resistance offered thereto
as there is a longitudinal slot in the side of the cylinder a (such as shown in Fig. 3)
for part of its length through which the lever arm d travels and immediately the
cylinder a is moved by the crank boff the plunger c the inuer end of the latter
comes below this slot and so air is freely admitted to the interior of the cylinder a
which therefore permits the shutter to travel (unrestrained) its full speed and so
give the shortest exposure.
In Fig. 2 the regulating arm e* is shown moved over to the opposite extreme
that is to the extreme left so that the plunger e is thereby pushed right home in
the cylinder a (as shown in dotted lines in Fig. 2) thus leaving a very small internal
area (or air space) or practically none at all.
When the shutter is operated the crank arm 6 will meet with great resistance in
dragging the cylinder a off plunger c as the small amount of air (if any) will be so
much attenuated and more air can only get to the interior by passing between the
plunger and the inner walls of the cylinder a and consequently the utmost
retardation takes place according to the more or less close or loose fit of the plunger
or piston c.
At intermediate positions of the regulating arin e intermediate durations of
exposure are obtained.
.

page_text: In place of the particular bell crank device de e pivotted at as shown in
Figs. 1 and 2 other mechanically equivalent devices may be used to move e in
or out of a or vice versa; or any other suitable means may be adopted to slide or
move the "non-attached part of the brake towards or away from the other or
"attached part."
"
Referring now to Figs. 3 and 4 :-
Fig. 3 is a plan, and
Fig. 4 is an edge view of another means of moving the parts one upon the
other.
In the arrangement shown in Figs. 3 and 4 the cylinder a is pivotted or other-
wise permanently attached to a bell crank arm pivotted at i having a slot în
which is held a pin or stud / fixed to some working part of the shutter mechanism.
The plungere in this case is pivotted at k to a slide m which travels in a fixed
guideway in or on the shutter frame (or camera case) n.
This slide m has a knob or projection othercon by which to move said slide in
the direction of the length of the cylinder and plunger.
The cylinder a is slotted towards its open end on one or both sides (as shown in
Figs. 3 and 4) and to any desired length or otherwise perforated to any desired
extent so that during part of the regulating stroke the end of the plunger will be
under or clear of said slots or perforations and thus no pneumatic retardation takes
place at such time while during the time the plunger lies inside the unperforated
or intact part of the cylinder the full retarding effect thereof will be felt.
Thus in setting the regulation by sliding plunger c more or less within a when
the shutter is operated the head of c will sooner or later coincide with the top end
of the slots (or equivalents) in a and thus vary and regulate the duration of
exposure as desired or the whole of the travel of a upon e may be on the intact
part of a or on the other hand may be entirely clear of the intact part of a.
In Figs. 3 and 4 the cylinder a is shown at about mid-stroke (that is with the
shutter held "open" for focussing) the regulation being set to perinit a very quick
exposure as retardation in the said case illustrated would only be of the slightest-
if any.
It will be quite obvious that the shutter or some working part thereof may be
so connected up to the cylinder or cap a (in either the arrangement shown in
Figs. 1 and 2 or that shown in Figs. 3 and 4) as to obtain the desired regulation
by drawing a off c or by forcing a onto c for some character of shutters, while for
some shutters the desired regulation may be obtained by moving the cylinder in
both directions that is first onto and then off the plunger or vice versa.
It will thus be seen that we can obtain by this invention a great desideratum in
the regulation and operation of photographic shutters riz. we can permit the
maximum speed or a very quick speed during the opening of the shutter and again 4
at the closing of the shutter the retardation or regulation occurring mainly during
the period when the shutter is full open in other words we obtain more than one
speed.
This feature however is of course only functional but serves as an illustration of
one of the advantages we obtain by the use of this invention.
Figs. 5, 6 and 7 show a modified arrangement and construction according to this
invention.
Referring to these figures:-
:-
Fig. 5 is a front view in elevation.
Fig. 6 a back view in elevation. And
a side or edge view in elevation of a complete shutter regulated
Fig. 7
according to this invention.
A is air cylinder or cap mounted so as to be capable of freely revolving in or on
bearing pivot or axis B.
B is pivot or bearing as and for the purposes hereinafter described.
C is the piston or plunger which is the part (in the case here illustrated)
permanently attached to or connected to the shutter riz.-by a pin D (pivotted to
4
5
5

page_text: the outer end of the plunger C) passing through the curved slot E in the shutter
disc or plate F & mounted in fixed position on crank disc G.
F is shutter disc or plate pivotted or otherwise connected to a second disc or
circular plate G by means of the pin D.
Gis disc or circular plate fixed to and carried by axis H carrying the crank
pin D.
I is milled head or handle fixed to H.
Jis spring barrel or case containing suitable coiled spring which is wound up
when the milled head I is rotated-in the direction to set the shutter-this rotation
also revolving the axle H and disc G and consequently the pin D acts as a crank
pin and the latter working in the curved slot E (in the disc F) in one complete
revolution of this crank disc G & pin D thereon-raises and lowers the shutter F.
The cylinder A is mounted as shown by being held rigidly in a collar or strap L
around same and this collar L terminates in (or the cylinder A has otherwise
fixed thereto) a pin or axis which can freely revolve in or on B.
This bearing or device B is made capable of sliding or moving as shown by
travelling in the slot or guideway M in the cross strap or bar N mounted and fixed
across the back of the shutter.
When the pivot or bearing B for A to revolve in or upon is placed about the
centre of the circle described by pin D (by placing B at the bottom of the slot M)
then the plunger C in the course of the entire revolution made by pin D will not
force C into A in any perceptible degree and therefore the minimum amount of
resistance or retardation is offered i.e. the speed is practically unrestrained.
If now the device B be slid or moved out to the extreme position shown in dotted
lines in Fig. 7 then it will be obvious that in the course of each revolution the
plunger C will be forced right home down to the bottom of A and thus the greatest
amount of resistance is offered at the time when the shutter is full "
open" for
exposure-practically no retardation taking place at the beginning and the end of
the exposure and consequently no time is lost in the raising and lowering (or
opening and closing) of the shutter.
As a modification of the foregoing
:
A tube of cylindrical or other suitable shape and open at each end may be
pivotted or mounted so as to be capable of swinging at about the centre of its
length and the moving part of the shutter has a tube or cap (corresponding in
shape) attached thereto to slide over (or slide into) this pivotted tube at one end
thereof while at the other end thereof another tube or cap of corresponding shape
may be mounted or arranged to slide over (or slide into) this said pivotted tube-
this third tube being drawn in or out by incans of a slide, bell, crank lever or other
suitable device so as to vary the internal area of the air chamber thus formed as
before described-each of these two slide tubes or caps being closed at their outer
ends as before the only difference from the first arrangement being that the air
chamber is formed in three parts instead of two.
If desired the regulating action can be obtained by a bellows or the like
arrangement one side or part of the bellows being connected to some working part
of the shutter and another side or part of the bellows connected to a slide or other
regulating device as before for varying the position of same so that the internal
area of the air chamber in said bellows is increased or diminished for the purposes
set forth.
Thus the air chamber is contracted or extended or both in any of the above
described manners or in any mechanically equivalent manner and the speed of the
shutter can be thus regulated in a very simple manner and without in any way
varying the leverage between the air chamber and the operating spring.
The index handle or regulating arm, slide, or lever by which the internal area of
the air chamber is varied can be held in position by set screw or clamp or in any
other suitable manner-as desired.
Any well known releasing device (or other equivalent or suitable devices) for

page_text: releasing the shutter, holding same open etc. may be adopted and applied as is well
understood.
As already set forth we wish it to be clearly understood that in regulating
photographic shutters according to the present invention by sliding the piston or
plunger into or onto the cylinder or cap (or vice versa) and thus altering the length
of the column of air or internal area of the pneumatic device we do not confine
ourselves to the details hereinbefore set forth because it will be obvious that this
adjustment of the parts the one upon the other may be obtained in numerous ways
and by numerous mechanical devices without in any way departing from the nature
of this present invention.
Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed we declare that what
we claim is:
1. In apparatus for regulating photographic shutters having a pneumatic cylinder
and piston (or equivalent) acting as the retarding device one part of which is
permanently attached to some working part of the shutter or shutter mechanism so
that the travel or movement of said attached part is always constant-the arrange-
ment and combination therewith of the "non-attached part" capable of being slid
or moved towards and away from such "attached part of the pneumatic retarding
device so as thus to vary and regulate the resistance offered by the air and
consequently the duration of the exposure given substantially in the manner and for
the purposes hereinbefore set forth.
"
2. In a spring actuated photographic shutter having a pneumatic brake or
retarding device the combination therewith of means for varying the internal area
(ie. the length of the column of air therein) or effective part thereof so that the
moving part of such brake performs the same constant travel under more or less
pneumatic restraint substantially in the manner and for the purposes hereinbefore
set forth.
3. In regulating devices for photographic shutters-the combination of a
pneumatic cylinder such as a attached or connected to some working part of a shutter
and a piston or plunger such as e capable of adjustment towards and away from a
(or a and c arranged rice versa) by means of a bell crank such as illustrated in
Figs. 1 and 2 or a slide such as illustrated in Figs. 3 and 4 substantially as and for
the purposes hereinbefore described.
4. In regulating devices for photographic shutters the arrangement and com-
bination of a piston such as C one end of which is always caused to describe a given
circle and a cylinder D mounted on a swivel or bearing which is capable of being
slid or moved to positions eccentric to the centre of said circle to thereby regulate
the speed of travel of the shutter substantially in the manner and for the purposes
hereinbefore described with reference to Figs. 5, 6 and 7 of the drawings hereunto
annexed.
5. The arrangement construction and combination of parts constituting our
improved pneumatic regulating device for photographic shutters acting in the
manner and for the purposes hereinbefore described and illustrated in the drawings
hereunto annexed.
Dated the onch deve of Vorab 1902
TONGUE & BIRKBECK,
34, Southampton Building, Chancery Lane, London, W.C.,
Agents for the Applicants.