Improvements in or connected with Instantaneous Shutters for Photographic Purposes.
Year: 1890

page_text: Date of Application, 3rd Apr., 1890
Complete Specification Left 3rd Jan., 1891-Accepted, 7th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in or connected with Instantaneous Shutters for
Photographic Purposes.
I, FRANCIS BEAUCHAMP, of The Poplars, Chadwell Heath, in the County
of Essex, Engineer, do hereby declare the nature of the said invention to be as
follows:-
This invention relates, firstly, to improvements in the construction and arrange-
ment of instantaneous shutter mechanism in which the shutter is intended to work
in the ordinary diaphragm slit of a photographic lens, and the improvements under
this head consist as follows:-
The casing or framework, containing the mechanism for operating the shutter
and for regulating the time occupied in its opening and closing, is secured in proper
position on the lens mount, and over the diaphragm slit thereof, by being screwed
or otherwise fastened to a split ring which is previously clamped on to the lens
mount, in such a position that when the said casing or framework is secured thereto
the shutter carried by such casing or framework is free to work easily in the
diaphragm slit of the said lens mount. The shutter is connected to a kind of cross-
head which works in or on suitable guides in the casing or framework. This
crosshead has a slot formed in it at right angles to the direction of its motion. A
crank or crank plate is arranged to turn on a suitable spindle, and a pin on the said
crank or crank plate takes into the slot in the aforesaid crosshead, so that whenever
the crank plate makes a revolution the shutter is caused by the crank pin to open
and close. One end of a coiled spring is secured to the casing or framework and
the other end to the crank plate, and means are provided for winding up the said
spring. The crank plate is prevented from being turned by the spring, until
required, by means of a catch or trigger which takes behind a stop or into a notch
on the said crank plate, the said stop or notch being so placed on the crank plate
that when the catch or trigger is engaged therewith the crank pin holds the shutter
in its closed position. It will now be understood that, assuming the spring con-
nected with the crank to be wound up, on releasing the catch or trigger the spring
will cause the crank to make a revolution, and the crank pin acting in the slot of
the crosshead will cause the shutter to open and close.
The invention relates, secondly, to improvements in mechanism for regulating
the time occupied in opening and closing instantaneous shutters. For this purpose
I employ a vulcanite friction disc arranged to turn on a centre fixed to the casing
or framework, concentric with the axis of the crank operating the shutter. This
vulcanite disc is rotated by the crank pin which engages therewith, or by means of
any other suitable connection with the crank axis, and friction is applied thereto
by two plates, between which it is placed, being pressed together with any required
degree of force by means of a screw and spring. The speed of movement of the
shutter is thus made dependent upon the friction exerted on the vulcanite disc by
the plates between which it is placed. Instead of the vulcanite friction disc, I
sometimes employ an air cylinder mounted concentric with the axis of the crank,
which axis passes through the centre of the said cylinder and carries a radial leaf
or piston which fits more or less closely to the ends and circumference thereof
somewhat after the manner of the pistons of certain kinds of rotary steam engines.
A radial partition is fixed at a given point in the cylinder and extends from the
circumference thereof to the crank axis or to the boss of the leaf or piston fixed
thereon. This leaf or piston stands at one side of the partition when the shutter
is closed and the crank actuating spring is wound up. When the spring is
released and the crank makes its revolution or partial revolution in order to open

page_text: and close the shutter to give the necessary exposure, the leaf or piston rotates also
in the air cylinder, driving the air before it through an adjustable hole in the
cylinder, or through any suitable adjustable opening or passage, until it comes to
rest on the other side of the aforesaid partition. By regulating the size of the hole
for the escape of the air, the speed of opening and closing the shutter, that is to
say the time of exposure, can be regulated at pleasure. Air enters behind the leaf
or piston through an appropriate hole in the cylinder to prevent the formation of a
partial vacuum behind the leaf or piston and the consequent retardation of the
same. By the employment of the rotary form of cylinder and piston I am enabled
to avoid the objectionable jerk that generally occurs in those time regulators now
in use, which consist of an air cylinder and reciprocating piston, when the crank
driving the said piston is passing its dead centre at the time when the shutter is
full open and is about to be closed again.
Both the friction and air time regulating apparatuses above described are
applicable to any shutter actuating mechanism in which a rotating or partially
rotating axis is employed.
The invention relates, thirdly, to improvements in the operating mechanism of
instantaneous shutters whereby a number of exposures, with any desired interval of
time between each, can be made with one winding up of the shutter actuating
spring. For this purpose I actuate the shutter by means of a crank rotated by a
coiled spring in a manner well understood, but I make the spring with sufficient
range to turn the crank the required number of times with one winding up of the
spring, and in order to prevent the crank from making more than one revolution,
and consequently one opening and closing of the shutter at a time, and to allow of
any required interval of time between each revolution, I arrange an escapement
lever which can either be operated by hand, or by the usual pneumatic releasing
device, a finger rotating in concert with the crank or crank axis is retained by a pin
or stop on the escape lever until the latter is moved by hand or by the pneumatic
releasing device, and the crank then makes a partial revolution sufficient to open
and close the shutter, giving an exposure, the aforesaid finger being stopped by a
second pin or stop on the escape lever. When the latter is pressed back by a
spring into its normal position, the said finger slips past the second pin or stop on
the escape lever and comes against the first pin or stop thereon where it is retained
until the escape lever is again actuated, when it is again released and the crank
makes another revolution effecting another exposure, and so on until the actuating
spring has rown down so that it will no longer drive the crank.
Dated this 3rd day of April 1890.
COMPLETE SPECIFICATION
Improvements in or connected with Instantaneous Shutters for
Photographic Purposes.
I, FRANCIS BEAUCHAMP, of The Poplars, Chadwell Heath, in the County of
Essex, Engineer, do hereby declare the nature of the said invention, and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accompanying sheet
of drawings and to the letters and figures marked thereon, that is to say :-
This invention relates, firstly, to improvements in the construction and arrange-
ment of the mechanism of what are known as instantaneous shutters in which the
shutters are intended to work in the ordinary diaphragm slits of photographic lenses,
and the improvements under this head are illustrated in Figures 1, 2, 3 and 4 of the
drawings where

page_text: Figure 1 is a front sectional elevation of apparatus with my improvements applied
thereto, the cover plate being removed;
Figure 2 is a similar view with the cover plate in place;
Figure 3 a back view, and
Figure 4 a section on line X X of Figures 1, 2 and 3.
The casing or framework A, containing the mechanism for operating the shutter B,
and for regulating the time occupied in its opening and closing, is secured in proper
position on the lens mount C, and over the diaphragm slit C₁ thereof, by being
screwed or otherwise fastened to a split ring D (shewn in side elevation in
Figure 2A) which is previously clamped on to the lens mount C by the
clamping screw D', in such a position that when the said casing or framework A is
secured thereto, the shutter B, carried by such casing or framework, is free to work
easily in the diaphragm slit C of the said lens mount C. A convenient method of
securing the casing A to the ring D is shown in the drawings and consists as
follows:-D are lugs cast with the ring D, each lug having a slot D³ formed
therein, (see Figure 2). A' and A² are studs on the sides of the casing A which
fit accurately into the slots D³. D' is a milled clamping nut which screws on to
the stud A2 and takes into a circular recess in the lug D so that when the casing A
is placed in position with its studs A¹ A2 in the slots D³, and the nut D* is screwed
up tightly, the casing A is held firmly on the ring D and cannot be lifted off because
the nut Ď takes into the recess in the lug of the ring D.
The shutter B is connected to a kind of crosshead E which works in guides E'
in the casing or framework A. The crosshead E has a slot E' formed in it at
right angles to the direction of its motion. A crank or crank plate F is secured to
a spindle or axis F! arranged to turn in a suitable bearing in the casing A, and a
pin on the said crank or crank plate takes into the slot E' in the aforesaid cross-
head E; so that whenever the crank plate makes a revolution, the shutter B is caused
by the crank pin to open and close. One end of a coiled spring Fis secured to the
casing A, or to the box F, containing the said spring, and the other end to the
spindle or axis F' of the crank plate. F is a milled button or handle fixed on
the spindle or axis F', and serves to wind up the said spring F. The crank plate F
is prevented from being turned by the spring F³, until required, by means of a
catch G on the trigger lever G', which catch takes into a notch F in the crank
plate F, or behind a suitable stop thereon, the said notch or stop being so placed
on the crank plate that when the catch G is engaged therewith the crank pin F³
holds the shutter B in its closed position.
It will now be understood that, assuming the spring F³ to have been wound up,
on disengaging the catch G from the notch F by means of the trigger lever G,
the said spring will cause the crank plate F to make a revolution and the crank pin F
acting in the slot E of the crosshead E will cause the shutter B to open and close.
The crank plate is prevented from making more than the portion of a revolution
necessary to open and close the shutter by the part F' coming against the catch G
by the time the shutter B is closed.
When it is desired to effect both the opening and closing of the shutter B in
quick succession, the trigger lever G¹ is held up long enough to allow the crank
to rotate far enough to both open and close the shutter and to bring the part F' of
the crank plate against the catch G; but if it desired to open the shutter, and
to hold it open for a comparatively long time, either to admit of focussing, or for
the purpose of long exposure of a plate, the trigger lever is raised to disengage the
catch G from the notch F and is then allowed to fall again; then, when the crank
has made a half revolution so as to open the shutter B, the part F8 of the crank
plate comes against the catch G, and the crank plate is thereby prevented from
rotating any further, until the catch G is again raised high enough to allow the
crank plate to pass clear of it.
The invention relates, secondly, to improvements in mechanism for regulating the
time occupied in opening and closing what are called instantaneous shutters. For
this purpose I employ a vulcanite friction disc H, see Figures 1, 2, and 4, arranged

page_text: to turn on a centre H¹ fixed to the casing or framework A concentric with the
axis of the crank plate F. This vulcanite disc is rotated by the crank pin F
which engages in a hole therein, or is otherwise rotated with the crank plate; and
friction is applied thereto by its being pressed between a plate H³ and the vulcanite
back plate A³ of the casing A, with any required degree of force by means of a
screw cap H³ screwed on the centre spindle H' and compressing a spring H*, by
which the two plates H2 and A3 are pressed together with the disc H between them.
The speed of movement of the shutter is thus made dependent upon the friction
exerted on the vulcanite disc by the plates between which it is placed.
Instead of the vulcanite disc, I sometimes employ an air cylinder I, see Figures 5
and 6 of the drawings, fixed concentric with the axis of the shutter actuating
crank F of Figures 1 and 4, the pin F2 of which takes into and drives a crank 1*
fixed on an axis I×× which passes through the centre of the said cylinder and carries
a radial leaf or piston I which fits more or less closely to the ends and internal
circumference thereof somewhat after the manner of the pistons of certain kinds of
rotary steam engines. A radial partition 12 is fixed at a given part in the cylinder I
and extends from the circumference thereof to the axis I** or to the boss of the
leaf or piston fixed thereon. This leaf or piston stands at one side of the partition
when the shutter B is closed and the crank actuating spring F³ is wound up. When
this spring is released, and the crank F makes its revolution or partial revolution,
in order to open and close the shutter to give the necessary exposure, the crank 1*
rotates also and with it the leaf or piston in the air cylinder, driving the air before
it through a hole in the cylinder I, or through any suitable adjustable opening or
passage until it comes to rest on the other side of the aforesaid partition. By
regulating the size of the hole, the escape of the air may be retarded, or accelerated,
and the speed of opening and closing the shutter, that is to say the time of exposure,
regulated accordingly at pleasure. In Figure 6 is shown a method whereby the
regulation can be effected by allowing the air in front of the leaf or piston I¹ to escape
with greater or lesser rapidity to the back thereof. For this purpose a cap 15 is
scrowed with a fine thread over the outside of the cylinder 1, and by turning this
cap round in one direction or other its inner face is made to approach nearer to, or
to recede further from the adjacent edges of the leaf or piston I, and of the
partition 12 so as to leave a greater or lesser space for the passage of air from one
side to the other of the piston or partition.
Air may be allowed to enter behind the leaf or piston through an appropriate
hole in the cylinder, to prevent the formation of a partial vacuum behind the leaf
or piston, and the consequent retardation of the same. By the employment of the
rotary form of cylinder and piston I am enabled to avoid the objectionable jerk that
generally occurs in those time regulators now in use which consist of an air cylinder
and reciprocating piston, when the crank driving the said piston is passing its dead
centre at the time when the shutter is full open and is about to be closed again.
Both the friction and air-time-regulating apparatuses, above described, are
applicable to any shutter actuating mechanism in which a rotating or partially
rotating axis is employed.
The invention relates, thirdly, to improvements in the operating mechanism of
what are called instantaneous shutters whereby a number of exposures, with any
desired interval of time between each, can be made with one winding up of the
shutter actuating spring. For this purpose I actuate the shutter B (see Figure 7
of the drawings) by means of a crank rotated by a coiled spring, in a manner
now well understood; but I make the spring with sufficient range to turn the crank
the required number of times with one winding up of the spring, and in order to
prevent the crank from making more than one revolution and consequently one
opening and closing of the shutter at a time, and to allow of any required interval
of time between each revolution, I arrange an escapement Jever J which can either
be operated by hand, by means of a button J' for example, or by the usual
pneumatic releasing device. A finger Jrotating in concert with the crank F, or
with the crank axis, is retained by a pin or stop on the escape lever J until the

page_text: latter is moved by the button J or otherwise in the direction of the arrow, far
enough for the pin or stop J' to clear the finger J, when the crank F makes a
partial revolution sufficient to open and close the shutter. B, thereby giving an
exposure; the aforesaid finger J is then stopped by a second pin or stop J* on the
escape lever J. When the latter is moved back by the spring J into its normal
position (that shown in the figure) the said finger J. slips past the second pin or
stop J on the escape lever J and then comes against the first pin or stop J³
thereon, where it is retained until the escape lever is again moved in the direction
of the arrow, when it is again released and the crank makes another revolution
effecting ancther exposure, and so on until the actuating spring has run down so
far that it will no longer drive the crank.
When it is required to obtain a larger number of exposures, with one winding up
of the actuating spring, than can be conveniently obtained by a coiled spring
arranged to act direct upon the axis of the crank, a more powerful spring may be
employed, mounted in a separate barrel K turning on a winding arbor L (see
Figure 8 of the drawings) the said barrel K being geared by a toothed wheel M
and pinion N to the axis of the crank F as will be readily understood. By this
means a large number of exposures may be obtained with a comparatively small
actuating spring.
I am aware that it is not new to arrange the shutter mechanism so that the
shutter works in the ordinary diaphragm slit of the lens mount, or to operate the
shutter by means of a spring actuated crank, or to regulate the time occupied in
opening and closing the shutter by means of a disc pressed with adjustable pressure
between two plates, or by means of an air cylinder with a rectilinearly reciprocating
piston and I desire to have it understood that I make no claim generally to such
arrangements or means.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that
what I claim is :-
First. In photographic shutter mechanism in which the shutter is arranged to
work in the ordinary diaphragm slit of the lens mount, the means for securing
the said shutter mechanism in position on the lens mount, such means consisting of
a split ring, clamped to the lens mount, and having lugs to which the case or
framework, containing the shutter mechanism, is fitted and secured, substantially as
hereinbefore described, and illustrated in Figures 1, 2, 3 and 4 of the drawings.
Second. In photographic shutter mechanism the arrangement for opening and
closing the shutter consisting of a spring-actuated crank-plate, a slotted crosshead
in which the crank-pin engages, and to which the shutter is connected, or with
which it is formed, and a stopping and releasing catch and trigger, combined,
arranged, and operating substantially as hereinbefore described, and illustrated
in Figures 1, 2, 3 and 4 of the drawings.
Third. In photographic shutter mechanism the means for regulating the time
occupied in opening and closing the shutter, consisting of a disc of vulcanite
rotated between two plates, the pressure of which against the said vulcanite disc
can be regulated by a screw and spring, substantially as herein before described, and
illustrated in Figures 1, 2 and 3 of the drawings.
Fourth. In photographic shutter mechanism the means for regulating the time
occupied in opening and closing the shutter, consisting of an air cylinder with a
radial partition and having a rotating radial leaf or piston operated by the axis
of the shutter-actuating crank, and means for regulating the escape of air from the
front of the said rotating leaf or piston, substantially as hereinbefore described,
and illustrated in Figures 5 and 6 of the drawings.
Fifth. In photographic shutter mechanism the arrangement whereby a number of
exposures, with any desired interval of time between each, can be made with one
winding-up of the shutter-actuating spring, such arrangement consisting of a spring-
actuated crank for operating the shutter, a stopping finger connected with the said

page_text: crank, and an escapement lever; combined, arranged, and operating substantially as
hereinbefore described, and illustrated in Figures 7 and 8 of the drawings.
Dated this Third day of January 1891.
F. BEAUCHAMP.
Per W. H. Beck,
115, Cannon Street, London, Agent.