Photographic Shutters.
Year: 1887

page_text: Date of Application, 16th June, 1887
Complete Left, 16th Apr., 1888
Complete Accepted, 18th May, 1888
of Photographic Shutters.
We, THOMAS RUDOLPH DALLMEYER, of 19 Bloomsbury Street, in the County of
Middlesex, Optician, and FRANCIS BEAUCHAMP, of High Cross, Tottenham, in the
County of Middlesex, Engineer, do hereby declare the nature of this invention to be
as follows:-
-
This invention has for its object improvements in apparatus for regulating exposures
in the use of photographic shutters.
Where the photographic shutter is opened and closed by the continuous movement
in one direction of a lever or driving part we give motion to such part by means of
automatic apparatus which we can regulate so as to move either faster or slower as
may be required. We employ for this purpose a spring barrel carrying a crank pin
and this, by a connecting rod, we connect with a lever which, in moving through a
small arc causes the opening and closing of the shutter. In connection with the
lever we provide a trigger-on pulling the trigger the lever is released and the spring
then acts upon it through the connecting rod, moving the lever from end to end of
its course. To adjust the speed of this movement we shift the joint coupling the end
of the connecting rod with the lever to or from the fulcrum of the lever. The further
this joint is placed from the fulcrum the more advantageously the force of the spring
is applied to effect the movement of the lever, and consequently the more rapidly the
movement is performed. Where the photographic shutter is of such a construction
as to require a movement of the actuating part in one direction for opening and in
another direction for closing it we employ another arrangement consisting of a spring
barrel and a train of wheels controlled by fly. On the axis of the spring barrel there
is a cam for moving in one direction the lever which gives motion to the shutter. The
movement in the other direction is caused by a spring. There is also on the same
axis a disc in which a notch is provided. This disc can be shifted around the axis so
as to alter the relative positions of the cam and the notch. By this adjustment the
length of exposure is regulated. The parts operate in the following manner :-
The clock-work being set free by a trigger or otherwise the cam travels round and

page_text: raises the lever; a finger jointed to the lever then falls on the periphery of the disc
in such a position as to support the lever in the position to which the cam has raised
it. Presently the notch in the periphery of the disc comes round and the finger drops
into the notch and allows the lever to descend or move inwards towards the axis of
the cam.
In this movement the shutter is closed and the finger remaining in the
notch in the disc brings the clock-work to rest.
Or according to another arrangement we provide an axis and a spring so applied as
to rotate the axis when set free. The axis has upon it a crank pin working in a slot
in a slide. The slide is thus moved to and fro. The slide has a projection upon it
adapted to operate against a finger in connection with the lever which moves the
shutter. The finger is moveable and can be so set as to be within the range of the
projection on the slide or to be entirely out of its way. In the first case the slide
imparts to the lever the motion requisite to rapidly open and close the shutter, and
immediately this is effected the movement of the axis is arrested by an arm upon it
coming against a stop pin inserted into a disc in a suitable position. When a slower
movement of the shutter is required, the finger is shifted away from the slide and
brought within range of a lever which receives a reciprocating motion from a cam
wheel mounted on the same axis with the crank pin but loosely. This cam wheel is
driven at a comparatively slow speed by a pinion on the shaft, giving motion to a
wheel on a counter shaft on which there is another pinion gearing into spur teeth
on the periphery of the cam wheel. As before, in the use of the apparatus the axis
is set free by a trigger and is allowed to run for a sufficient time to open and close
the shutter, which done it is brought to rest by a stop pin, as already explained, but
this stop pin is now set so as to allow the axis to turn through a larger angle than in
the former case.
Sometimes a cam preferably of conical form is employed. The axis of the cam is
driven by a train of wheels controlled by a fly. The lever for working the shutter
rests on the surface of the cam and drops into a recess in it when the recess comes
round. Thus the movement is obtained which causes the opening and closing of the
shutter. The cam is moveable lengthwise of the axis to bring different parts of the
recess into operation and the recess being suitably formed the duration of the exposure
is thereby adjusted to the length required.
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page_text: of Photographic Shutters.
We, THOMAS RUDOLPH DALLMEYER, of 19 Bloomsbury Street, in the County of
Middlesex, Optician, and FRANCIS BEAUCHAMP, of High Cross, Tottenham, in the
County of Middlesex, Engineer, 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 apparatus for regulating exposures
in the use of photographic shutters.
Where the photographic shutter is opened and closed by the continuous movement
in one direction of a lever or driving part we give motion to such part by means of
automatic apparatus which we can regulate so as to move either faster or slower as
may be required. We employ for this purpose a spring barrel carrying a crank pin
and this, by a connecting rod, we connect with a lever which, in moving through a
small are causes the opening and closing of the shutter. In connection with the lever
we provide a trigger-on pulling the trigger the lever is released and the spring
then acts upon it through the connecting rod, moving the lever from end to end of
its course.
To adjust the speed of this movement we shift the joint coupling the end
of the connecting rod with the lever to or from the fulcrum of the lever. The further
this joint is placed from the fulcrum the more advantageously the force of the spring
is applied to effect the movement of the lever, and consequently the more rapidly the
movement is performed. Where the photographic shutter is of such a construction
as to require a movement of the actuating part in one direction for opening and in
another direction for closing it we employ another arrangement.
We provide
an axis and a spring so applied as to rotate the axis when set free.
The axis has upon it a crank pin working in a slot in a slide. The slide is thus
moved to and fro. The slide has a projection upon it adapted to operate against a
finger in connection with the lever which moves the shutter. The finger is move-
able and can be so set as to be within the range of the projection on the slide or to
be entirely out of its way. In the first case the slide imparts to the lever the motion
requisite to rapidly open and close the shutter, and immediately this is effected the
movement of the axis is arrested by an arm upon it coming against a stop pin
inserted into a disc in a suitable position. When a slower movement of the shutter
is required, the finger is shifted away from the slide and brought within range of a
lever which receives a reciprocating notion from a cam wheel mounted on the same
axis with the crank pin but loosely. This cam wheel is driven at a comparatively
slow speed by a pinion on the shaft, giving motion to a wheel on a counter shaft on
which there is another pinion gearing into spur teeth on the periphery of the cam
wheel. As before, in the use of the apparatus the axis is set free by a trigger and is

page_text: allowed to run for a sufficient time to open and close the shutter, which done it is
brought to rest by a stop pin, as already explained, but this stop pin is now set
so as to allow the axis to turn through a larger angle than in the former case.
In order that our said invention may be more fully understood and readily carried
into effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front elevation of the first arrangement, the shutter employed being
that described in the specification of a former patent granted to us dated the 22nd
day of April 1887 No. 5903. It is opened and closed by the pin a as it travels in
one direction from one end to the other of the slot 6-The pin a is embraced by a
fork on the lever e which is pivotted at c¹, the pivot e¹ being carried by an arm d
fixed to the casing of the shutter. The lever c carries a pine which engages with
notches f,, in the trigger g-h is the cover of a spring box fixed to a projection j
on the case of the shutter. The spring tends to cause the cover h to turn about the
centre pin pivotted to the cover is a rod whose other end is pivotted to the
lever cits point of attachment to the lever can be varied, the pivot being free to
slide along the slot in the lever, a thumb nut being provided to secure it in any
position. By varying the point of attachment the leverage of the spring is varied
and the time of exposure regulated.
In working the apparatus the lever e is swung over until the pin e engages with the
notch f, the shutter being closed in that position as well as in the position shown in
the drawing. When the trigger is pressed the pin e is released, and the spring
swings the lever back again, thereby first opening the shutter and then closing it
again. The notch f¹ is provided for long exposures. When the pin e engages with
this notch the shutter is fully open and so remains until the trigger is pressed by
the operator, when the spring brings back the lever as before described and closes
the shutter.
Figures 2 to 7 illustrate the second arrangement.
Figure 2 is a side elevation.
Figure 3 is a plan.
Figure 4 is a section on the line x. x. Figure 3.
Figure 5 is a front elevation.
Figure 6 is a section on the line y, y, Figure 5.
Figure 7 is a section on the line, , Figure 5.
A is an axis which is fixed to the handle A¹.
B is a spiral spring tending to rotate
the axis A. The axis A has upon it a disc C carrying a crank pin C working in a
transverse slot D¹ in the slide D. This slide is therefore moved to and fro as the
axis rotates. The slide D works in guides E E' and carries an arm or projection D².
F is the lever which works the shutter. It is fixed to an axis F to which is also
fixed a swinging frame G. One of the sides of this frame carries a pin, to which
one end of the spring H is fixed. This spring therefore tends to keep the arm Fin
the position shown in Figure 5.
The frame G carries a stop or finger G₁ which has a pin G³ projecting to the
outside of the apparatus. The pin enters a slot in the lever J pivotted at J' by
which the finger G₁ can be moved to and fro. When it is in the position shown in
figure 5 it lies in the path of the projection 12 which in its motion carries it with
it but it is brought back again by the spring H as soon as it is free the arm F is thus
swung to and fro. When however the finger G and its pin G2 are in the position
shown in figure 7, and in dotted lines in figures 3 and 5, the finger G² no longer lies
in the path of the projection D2 and ceases to be actuated by it; it now however lies
in the path of the swinging lever K which has upon it the projection K¹ which bears
against the cam L. The cam L is in the form of a broken circle (see figures 4 & 7)
being continuous except at L'. When the projection K¹ drops into the break L' in
the cam the lever F is free to assume the position shown in figure 5 and the shutter is
closed. When the cam L begins to turn the shutter is at once opened and remains fully

page_text: open until the cam L has performed a complete revolution (in figure 7 it is shown
half way round). When the projection K¹ of the lever K again drops into the
break L and the lever F is free to be brought back by the spring H, and the shutter
again closes.
The cam wheel L is driven by the pinion M on the spring axis which gears with
the wheel N on the counter shaft N', which also carries the pinion O gearing with the
toothed wheel P on the periphery of the cam wheel. The axis of the cam wheel L
carries the finger on the outside of the apparatus-This finger Q forms the trigger,
being retained in any position by a peg put into one or other of the holes in the face
of the disc R-When released by pulling out the peg it revolves until arrested by the
spring stop S.
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. Apparatus in which the exposure is varied by altering the leverage of a spring
upon the arm actuating the shutter substantially as described.
2. The arrangement substantially as described and shown in Figure 1.
3. Apparatus for regulating the exposure in which the lever actuating the shutter
is moved to and fro or in one direction only by one or other of several parts which
reciprocate at different speeds substantially as described.
4. The apparatus substantially as described and shown in Figures 3 to 7.
TIL: 1 Cal
A
1 1000