Improvements in or relating to Photographic Shutters.
Year: 1890

page_text: Date of Application, 9th Aug., 1890
Complete Specification Left, 9th Jan., 1891-Accepted, 28th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in or relating to Photographic Shutters.
A. communication from abroad by THE BAUSCH AND LOMB OPTICAL COMPANY:
Body Corporate under the Laws of the State of New York, having its principal
Office and Works at Rochester, New York, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, & 323, High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion to be as follows:-
The improved shutter consists of a series of leaves grouped around a central
opening in a case or body, pivoted at their outer ends, and connected to a recipro-
cating ring by which they may be opened and closed in unison. A spring actuated
drum combined with detents, adjusting devices, and tripping devices, admits of the
leaves being adjusted to produce an aperture of variable size for admitting light
to the lens and of the aperture being opened and closed at will for time
exposures, or of its being opened and closed at one operation for "instantaneous
exposures.
:
"
An angular case or shell forms a portion of the lens tube or is arranged at
either end of the tube. It contains a series of thin blades or leaves sustained at
the outer cud by a pivot and provided with a crank pin. One of the blades is
formed double or with two leaves.
A ring is perforated to receive the crank-pins of all the leaves, so that when
moved in one direction it will swing the leaves inward and cause them to overlap
and close the opening, while on being moved in the opposite direction it will swing
the blades outward and produce a gradually increasing aperture.
At its top the ring carries a stud projecting into a slot in a link which is
The free end
pivoted and provided with a stud entering a slot in a pivoted plate.
of this plate is connected by a pivoted link to the free end of a vibrating an.
The arm and link constitute jointly a toggle or knee lever. The arm swings on
a coiled spring
the hub of a rotating drum pivoted to the frame and containing
which tends constantly to turn the drum to the right. The arm has on its back
a stud which enters a restricted opening in the base of the drum, so that when the
drum is turned to the right or left the arm is carried with it.
The link before mentioned has its pivot mounted on a lever pivoted to the
frame that it may swing to the right and left, carrying with it the link, so as to
change the distance of the stud from the fulcrum of the swinging arm. Although
the arm moves always through the same distance, this change in the position of
the stud will cause it to impart a greater or less movement to the link, and
through the latter to the shutter blades, so as to vary the size of the central
aperture between them. The lever carries a stud which enters an eccentric
groove in a rotary disc. This disc is roughened on the edge so that it may be
turned by the fingers and provided with numbers or graduations so that by simply
turning this disc to the required point the size of the aperture through the
shutter, whether for focussing purposes or for exposure, may be regulated at will.
The shutter is closed by turning the drum to the left by means of its handle,
and when thus set, it is locked by means of a lever, the notched end of which
engages a stud on the drum. The stop lever is slotted to receive the pivot pin,
so that the lever may turn on its pivot and also slide end wise. The end of the
stop lever is connected to a tube or cylinder sliding over a tube connected by a

page_text: tube with an elbow lever or other air forcing device, so that when the bulb is
squeezed the lever unlocks from the stud and allows the drum to turn forward
under the influence of the spring carrying it with the arm.
27
When instantaneous views are required, the drum is permitted to turn
forward to its extreme limit of movement during which the arm and link swing,
thereby opening the shutter, and, finally, closing it again. The vibration of the
lever causes the link to swing the arm upward and downward. The arm vibrates
the link and the latter raises and lowers the ring by which the blades are
moved.
In order to stop the shutter when opened to make "time" exposures, a
forked lever is pivoted so that its end may be set in the path of the stud.
A
spring acts at one end on the forked lever to throw its end out of the path of the
stud, while at the other end the same spring acts to urge the locking lever
upward and to the left. The locking lever carries a stud to act on the forked
lever. Another lever pivoted to the frame has, at its lower end a pin acting on
the forked lever, so that as the said lever is turned to the right it will hold the
forked lever down and render it wholly inactive. If the lever is thrown over, it
allows the end of the forked lever to rise into the path of sturl.
When the forked lever is thus free, the action of the parts is as follows:-
If the shutter is set for action, the first impulse of the bulb will cause the locking
lever to turn on its pivot and disengage from the stud. The drum will turn
forward into position, when the stud will meet the forked lever and be stopped,
holding the shutter open. The locking lever is now permitted to fall so that its
stud will pass below the end of the forked lever. If the locking lever is now
operated a second time, the stud, lifting the end of the forked lever, causes the
latter to disengage from the stud, whereupon the parts complete their revolution
closing the shutter.
In order to retard the motion of the parts, and to prevent concussion, the drum
is provided with a transversely adjustable slide connected at one end by a link to a
pivoted lever. The rotation of the drum causes the link to vibrate the said lever.
Its vibration is resisted by a closed cap or cylinder pivoted to its end and sliding
over a plunger so fitted that the air can escape but slowly between them from the
interior. This confinement of the air retards the motion of the cap, which in turn
retards the movement of the drum and the shutter blades. By moving the slide
and thus changing the distance between the end of the link and the pivot of the
drum, the leverage between the parts and the distance through which the cap is
moved may both be varied, so that the retarding effect is modified both by
changing the length of movement of the parts and the leverage through which
the spring acts upon them.
The movement of the slide is effected by a rotary disc having in its back a
spiral groove engaging a stud on the face of the slide. The operator has only
therefore to turn the disc in order to vary the speed at which the parts move in
opening and closing.
Dated this 8th day of August 1890.
WM. P. THOMPSON & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Photographic Shutters.
A communication from abroad by THE BAUSCH AND LOMB OPTICAL COMPANY,
Body Corporate under the Laws of the State of New York, having its
principal Office and Works at Rochester, New York, United States of
America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.1.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, & 6, Bank Street,

page_text: eccentric groove in a rotary disc 1, Figure 12. This disc has milled edges, so
that it may be turned by the fingers, and is provided with numbers or graduations,
so that, by simply turning this disc to the required point, the size of the aperture
through the shutter, whether for focussing purposes or for exposure, may be
regulated at will.
The shutter is closed by turning the drum to the left by means of its handle,
and, when thus set, it is locked by means of a lever L, the notched end of which
engages a stud on the drum (see Figure 15). The stop-lever I is slotted at 1, to
receive the pivot pin 4, so that the lever may turn on its pivot and also slide
endwise. The end of lever I is connected to a tube or cylinder M, sliding over a
tube M', connected by a tube M with an elbow-lever M³, or other air-forcing
device, so that, when the bulb is squeezed, the lever L unlocks from stud 13 and
allows the drum to turn forward under the influence of the spring carrying with
it the arm H.
::
When instantaneous views are required, the drum is first set as shown in
Figures 10 and 15 and is then permitted to turn forward to its extreme limit of
movement, during which the arm H and link G swing from the position shown in
Figures 10 and 15, first, to the position shown in Figures 9 and 16 thereby opening
the shutter, and, finally to the position shown in Figure 8, thereby closing it again.
The vibration of lever H causes the link G to swing arm F downward and upward.
Arm F vibrates link D and the latter lowers and raises ring C, by which the blades
are moved.
In order to stop the shutter, when opened to make "time" exposures, the forked
lever is pivoted at o, so that its end may be set in the path of the stud / on
arm H, as seen in Figure 16. A spring acts at one end on the lever Q, to throw
its end out of the path of stud h, while, at the other end, it acts to urge the lever L
upward and to the left. Lever I carries a stud to act on lever O. A lever P,
pivoted to the frame, has at its lower end a pin 7, acting on lever O, so that, as
lever P is turned to the right, as in Figure 20, it will hold lever O down and
render it wholly inactive. If lever P is thrown over, as shown in dotted lines, it
allows the end of lever O to rise into the path of stud h.
When the lever O is thus free, the action of the parts is as follows:-
If the shutter is set for action with the parts in the position shown in Figure 15,
the first impulse of the bulb M3 will cause the lever L to turn on its pivot and
disengage from stud 13.
The dram will turn forward into the position shown in
Figure 16, when the stud will meet lever O and be stopped, holding the shutter
open. The lever L is now permitted to fall so that its stud will pass below the
end of lever O. If lever L be now operated a second time, the stud 1, lifting
the end of lever O, causes the latter to disengage from stud h, whereupon the parts
complete their revolution, as seen in the position shown in Figure 17, closing the
shutter.
In order to retard the motion of the parts, and to prevent concussion, the drum is
provided with a transversely adjustable slide t, corected at one end by a link t2,
to levert, pivoted at /, Figure 18. The rotation of the drum causes the link t² to
vibrate lever t. Its vibration is resisted by a closed cap or cylinder T, pivoted to
its end and sliding over a plunger T, so fitted that the air can escape but slowly
between them from the interior. This confinement of the air retards the motion of
the cap T, which, in turn, retards the movement of the drinn and the shutter
blades. By moving the slide, and thus changing the distance between the end of
the link and the pivot of the drum, the leverage between the parts and the
distance through which the cap T is moved may both be varied, so that the
retarding effect is modified both by changing the length of movement of the parts
and the leverage through which the spring acts upon them.
The movement of the slide is effected by a rotary disc, U, having in its back, as
in Figure 19, a spiral groove u, engaging a stud on the face of the slide. The
operator has only, therefore, to turn the disc U in order to vary the speed at which
the parts move, in opening and closing,

page_text: Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. In a
photographic shutter, the series of pivoted leaves all operated by the
ring C which has a sliding, instead of a rotating, motion.
2. In a photographic shutter having a series of pivoted leaves or blades B
substantially as described, a double leaf, or leaf with an opening therein to admit
the ends of the other leaves, whereby leakage of light at the centre is prevented.
3. The pivoted leaves and the ring to actuate them, combined with spring-
actuated mechanism to move the ring to and fro, and suitable detenting devices
substantially as described, to control the action of the parts.
4. In combination with the pivoted blades and a spring mechanism to actuate
them, a pneumatic retarding device and means for changing the length of its
movement in relation to the movement of the blades.
5. In combination with a spring-actuated photographic shutter, a retarding
device and means for changing the leverage between it and the operating spring.
6. In combination with the shutter blades and the spring-actuated drum, the
levers and O and their actuating spring.
7. The pivoted blades, and the spring-propelled drum to move them, in com-
bination with the disc I, and its connections, substantially as shown, to vary the
movement of the blades and the size of the aperture.
Dated this 8th day of January 1891.
WM. P. THOMPSON & CO.,
Agents for the Applicant.