aro KHOWAD Shutters.
Year: 1887

page_text: Improvements 111 What aro KHOWAD
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:-
According to this invention the shutters are formed of two flat plates meeting
together in a line which passes across the centre of the lens-the plates being capable
of being moved away from one another in a straight path. To cause the shutters to
simultaneously move towards or from one another two lever arms are used-the axes
of the arms are in proximity to one another and the arms are there geared together
by a toothed quadrant or one gearing into a toothed quadrant in the other. In each
arm is a slot and a pin projecting from one shutter is made to enter a slot in one lever
arm and a pin on the other into a slot in the other arm. A crank pin carried by a
small crank axis enters a slot in one of the lever artus. A stop is placed in the path
of this crank pin which allows the axis to have nearly but not quite a complete turn
given to it.
When turned in either direction from one extremity of its movement to the other
it first opens the shutters and then closes them. A coiled spring tends to turn the
axis in one direction. When the apparatus is to be used a notched or ratchet wheel
which is fast on the crank axis has nearly a complete turn given to it in a direction to
wind up the spring and the notched or ratchet wheel is then retained by a pawl or
catch.
When the shutters are to be opened for a rapid exposure the pawl is withdrawn from
the notches in the wheel. The spring then gives nearly a complete turn to the crank
axis and rapidly opens and again closes the shutters.
The duration of the exposure can be varied by coupling one or other of the arms
to a third arm to the axis of which a friction brake may be applied-or it may be
varied by varying the strength of the coiled spring. A convenient way of varying
the strength of the spring is as follows. The outer end of the coiled spring is fixed

page_text: and the inner end is fastened to a bush which turns loosely on the crank axis. The
bush has an arm extending from it and carrying a pin which goes through a slot in
the ratchet wheel and into a disc which lies against its face. The disc has a handle
upon it by which a partial turn around the axis can be given to it according to the
length of the slot in the wheel-and it can be clamped to the wheel in any of the 5
various positions into which it can be turned-by a binding nut screwed on to the end
of the crank axis. This locks the bush the crank axis and the ratchet wheel all
together. When the nut is slackened the spring can be more or less wound up or
unwound by turning the disc and the parts can then again be locked together.
The ratchet wheel can if desired be turned from the back end of the camera by 10
continuing its spindle to the back and by making it telescopic. The back end of the
camera may in this case be made to carry the ratchet wheel and pawl-so that the
winding up of the shutter and the releasing of it can both readily be effected by
the operator from the back.
By making the shutters and actuating them in the manner above described the 1
shutters and mechanism can be made of much smaller width than shutters as hereto-
fore made as they are composed simply of flat plates lying one over the other.
CARPMAEL & Co.,
Agents for the Applicants.
20

page_text: COMPLETE SPECIFICATION.
Improvements in what are known as Instantaneous 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 ascer-
tained in and by the following statement :-
According to this invention the shutters are formed of two flat plates meeting
together in a line which passes across the centre of the lens the plates being capable
of being moved away from one another in a straight path. To cause the shutters to
simultaneously move towards or from one another two lever arms are used-the axes
of the arms are in proximity to one another and the arms are there geared together
by a toothed quadrant on one gearing into a toothed quadrant on the other. In each
arm is a slot and a pin projecting from one shutter is made to enter a slot in one lever
arm and a pin on the other into a slot in the other arm. A crank pin carried by a
small crank axis enters a slot in one of the lever arms.
The axis can be turned by a coiled spring and whenever allowed to turn can be
arrested by a stop when it has made a complete turn or approximately so.
When allowed to turn from one extremity of its movement to the other it first opens
the shutters and then closes them.
The duration of the exposure can be varied by applying an adjustable friction brake
or by varying the strength of the coiled spring.
The apparatus shewn on sheet 1 of the drawings hereunto annexed is suitable for
being used with a camera fitted with an ordinary dark slide. The apparatus shewn on
sheets 2 and 3 can be used without any dark slide-the opening of the shutters in
this apparatus can also be controlled from the back end of the camera and can be used
in cameras adapted for taking a number of pictures quickly in succession.
The apparatus shewn on sheet 4 has in it an adjustable friction brake for varying
the duration of exposure.
On sheet 1 Figure 1 is a front view of the shutter mechanism. Figures 2 and 3
are front views with the front plate removed-in Figure 2 the shutters are in their
closed position and in Figure 3 are shewn fully opened. Figure 4 is an edge view
and Figure 5 a section on the line a b Figure 1-Figure 6 is a longitudinal section
through the casing within which the shutters are carried. Two or more views of
each of the moving parts of the mechanism are also shewn separately-these are
marked with the same letters of reference as in the other figures.
The casing of the shutter mechanism is composed of a plate A the front face of
which has recesses formed in it for the shutters and levers which work them to lie in-
whilst the back face has secured to it a short screw threaded metallic tube B to be
screwed on to the outer end of the lens tube-The front of the plate A is covered.over
by the cover plate C.
5
DD are the two shutters formed of thin flat metallic plates they can be slidden

page_text: towards or away from one another in a rectangular recess in the front of the plate A-
EE are the levers by which the shutters are moved-one end of each overlies one of
the shutters and the other end lies in a recess formed in the plate A-these ends gear
with one another as shewn--F are the pins on which the levers turn. In each lover
is a slot E into which a pin D¹ on one of the shutters enters.
In one of the levers is also a slot E2 into which enters a crank pin G₁ carried by a
disc G³ fixed on a spindle G-this spindle passes through the cover plate C of the casing
and can be revolved by a spring in the following manner.
A bush H is slipped loosely on to the spindle, it has a tooth H' on its exterior for the
inner end of a long coiled spring I to hold onto. The outer end of this spring is
secured to the side of a cylindrical casing N within which the spring is enclosed and
which is fixed to the exterior of the cover plate C-On the bush H is a disc H2 which
has a pin H³ projecting from it. This pin passes through a slot K' in a disc K which
is placed on to the spindle and fits to it so that spindle and disc turn together.
Outside the disc K is another disc L which can turn loosely around the spindle-
this disc has a small hole L' formed through it into which the end of the pin H³
enters so that by turning the disc the bush H can be turned and the coil spring wound
up for a further half turn or more or less as far as the slot K¹ will allow of the pin H³
being moved.
The discs K and I can then be clamped together by the screw nut M screwed onto
the end of the spindle and in this way the force with which the spring tends to turn
the spindle G can be regulated. The plate which carries the cylindrical casing N has
a projection N standing out from its inner side which serves as a stop for the
crank pin G¹ on the spindle G to come against when the spindle has been caused
to make approximately a complete turn in one or other direction and against
whichever side of the stop the crank pin may be resting the shutters will be
closed.
The disc L has a roughened rim around it so that it can be turned by hand. The
dise K has ratchet teeth formed around it so that it may be retained by a pawl O in
whatever position it may be turned into.
To set the mechanism into a state ready for use the disc L has approximately a
complete turn given to it by hand so as to cause the crank pin G' to be carried round
from one side of the stop N¹ to the other and the spindle is prevented by the pawl O
from being turned back again by the spring.
As this is being done the spring is wound up the shutters also first open and again
close but this is immaterial as the dark slide in front of the plate would not then have
been withdrawn. The shutters are then in readiness for being used and when the
dark slide has been withdrawn from in front of the plate can at any time be made to
open and again close by a finger being pressed upon the tail end of the pawl O and so
releasing this pawl from the ratchet teeth on the disc K and allowing the spindle to be
turned by the coiled spring.
We will now describe the arrangement of the mechanism shown at Figures 7, 8,
and 10.
9
Figure 7 is a side elevation of a camera with the shutter mechanism fitted to it.
Figure 8 is a front view of the slide which carries the lens and shutter mechanism.
Figure 9 a similar view with the lens and front plate of the slide removed and
Figure 10 is a section taken through the casing which contains the spring used for
opening and closing the shutters.
The parts which are similar to those shown in Figures 1 to 6 are marked with the
same letters of reference as in those figures.
A is the back plate of the slide which contains the shutter mechanism-C is the
front or cover plate which carries the lens tube in the same way as the lens tube has
been carried by the ordinary front slide of a camera-D are the shutters-E the levers
which move them-F the pins on which the levers turn. The levers are geared
together by a pin on one entering a slot in the other-G'is a crank pin on a spindle G
entering a slot E' in one of the levers-G* is a projection on the same spindle which
abuts against a lever stop P.

page_text: A tooth Px on the opposite end of the lever P is by a spring P¹ kept pressed against
the notched circumference of a small wheel Q¹ on the forward end of a telescopic
spindle Q. The rear end of the spindle is carried as shown by a universal joint
attached to the rear end of the casing of the camera and on the rear end of the spindle
is a milled head by which it can be turned.
When the spindle is turned one or other of the teeth or projections of the small
wheel Q¹ act against the tooth Px on the end of the lever and move the opposite end
of the lever out of the path of the projection G* on the spindle G this liberates the
spindle G and allows it to be turned by the coiled spring. Immediately that the tooth
of the wheel Q¹ has been moved beyond the tooth Px the lever P is brought back to
its former position by the spring P and its end again comes into the path of the
projection G and again arrests the spindle G when it has made one complete
revolution.
Each time that the mechanism is to be used the spring is wound up by giving one
complete turn to the cylindrical casing within which the spring is contained and the
casing is retained by a pawl engaging with ratchet teeth formed around its circum-
ference.
When focussing the shutters can be held open by placing a pin into a-hole S so that
it shall stop the spindle G when it has made half a revolution.
The speed with which the shutters are made to open or close as above described we
prefer to regulate by adjusting the extent to which the spring is wound up-it may
however be regulated by applying more or less friction to impede their movement.
This may be effected by applying a friction band which by a screw can be tightened
up more or less around the exterior of the discs on the spindle G of apparatus similar
to that shown at Figures 1 to 6. Or one of the levers E of such apparatus may have
a pin projecting from it to enter a slot in a lever arm R-and a friction clip or band
made to embrace the axis of this lever as shown at Figures 11 and 12.
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. Constructing so called instantaneous photographic shutters of two plates meeting
in a line which passes across the centre of the lens and which are capable of being
moved in a straight path towards or away from one another and are so coupled
together that when one is moved in one direction the other is moved in the opposite
direction.
2. Giving a to and fro motion to the plates by a crank pin on an axis turned by
a spring and which when allowed to turn makes one complete revolution or approxi-
mately so.
3. Constructing so called instantaneous photographic shutters of two plates moveable
towards or away from one another in a straight path by levers coupled together both
turn together and one moved to and fro by a crank pin on an axis which can be made
to make one complete revolution or approximately so.
4. The construction of instantaneous photographic shutter mechanism substantially
as herein before described with reference to Figures 1 to 6.
5. The construction of instantaneous photographic shutter mechanism substantially
as herein before described with reference to Figures 7 to 10.
Dated this 11th day of Jul 1888
THOS. R. DALLMEYER.
F. BEAUCHAMP.