Improvements in Photographic Shutters and Iris Diaphragms therefor.
Year: 1899

page_text: Date of Application, 6th Dec., 1899
Complete Specification Left, 7th Aug., 1900-Accepted, 3rd Nov., 1900
PROVISIONAL SPECIFICATION.
Improvements in Photographic Shutters and Iris Diaphragms therefor.
We, THE THORNTON-PICKARD MANUFACTURING COMPANY LIMITED, of Atlantic
Road, Altrincham, in the County of Chester, Photographic Apparatus Manu-
facturers, and CHARLES GODFREY WOODHEAD, of the same place, Works Manager,
do hereby declare the nature of this invention to be as follows:--
This invention relates to the type of photographic shutter in which an iris
diaphragm and a shutter comprised of plates or blades are interposed between
the members or glasses of the lens and it is designed to construct these parts
as thin as possible or to take up as little space laterally as possible and also
to improve the construction and arrangement of the parts to simplify the con-
struction to render them more easy of manipulation and less liable to get out of
repair.
The base plate of the iris diaphragm to which the leaves are pivoted we con-
struct of thin sheet metal with a number of small tongues of circular semi-
circular or other suitable shape punched or stamped out to form pivots for the
leaves, with a flange around the edge to stiffen the plate. The tongues are bent
up to receive the leaves and then turned or flattened back to hold the leaves in
position.
The leaves are stamped with holes at one end to fit into the pivots formed by
the tongues of the base plate and provided with pins or projections at the other
end to fit into or engage the slots of the slotted plate.
The slotted plate is also stamped from thin sheet metal with the requisite
number of slots and formed with a flange at the edge to stiffen it and fit into
the flange of the base plate the two being made to move relatively to each
other. At present we prefer to form lugs or extension pieces on the slotted
plate to attach it to the frame of the shutter and allow the base plate to rotate
or move. The slotted plate may however be caused to move or a movement in
reverse directions may be given to both plates.
The shutter blades are connected to and actuated by the rotating operating
disc as heretofore.
The operating disc may be rotated as before to set the shutter by a knob or
projection attached to it but we prefer to attach to it a pinion rotated by a
quadrant working on a pivot the projecting end of the quadrant serving as a
lever to rotate the disc it being so placed as to balance (in appearance) the releas-
ing lever on the other side of the shutter.
The releasing lever is actuated by a pneumatic plunger piston or bulb of
ordinary construction and a pneumatic plunger or similar timing device is
connected by a lever to the shutter blades.
The lever connected to the pneumatic timing device is pivoted on a movable
fulcrum carried at one end of a second pivoted lever which can be readily moved
by a cam or other device to move to change the position of the pivot or fulerum of
the first or connecting lever. This first lever is connected by a short link with
the rotating setting disc and when at its fastest speed the pivot by which the

page_text: link is attached to the lever is coincident or concentric with the centre of the
disc so that the movement of the disc does not move the lever. The alteration
of the fulcrum of the lever throws this pivot out of centre with or eccentric to
the disc centre so that the rotation of the disc draws the end of the lever con-
nected to the pneumatic timer away from it and so lengthens the travel of the
timer and consequently lengthens the time of exposure.
We at present prefer a cam to operate the second lever with a slot or groove
in which, the free end of the lever works but an eccentric slide or other device
may be employed for the same purpose.
In another modification the first lever is pivoted on a fixed fulcrum and the
link attached to the rotating disc always moves the lever a given distance and the
escape of air made to depend on a hole or orifice the size of which can be enlarged
or reduced by a rotating plate of pelix or other suitable shape.
An index plate both for the iris diaphragm and for the timer is affixed to the
shutters and index fingers or pointers moving along the same are employed tɔ
set or adjust the parts or to indicate the position at which they are set.
Dated this 5th day of December 1899.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Photographic Shutters and Iris Diaphragms therefor.
We, THE THORNTON-PICKARD MANUFACTURING COMPANY LIMITED, of Atlantic
Road, Altrincham, in the County of Chester, Photographic Apparatus Manu-
facturers, and CHARLES GODFRED WOODHEAD, of the same place, Works Manager,
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 the type of photographic shutter in which an iris
diaphragin and a shutter comprised of plates or blades are interposed between
the members or glasses of the lens and it is designed to construct these parts
as thin as possible or to take up as little space laterally as posible and also to
improve the construction and arrangement of the parts to simplify the con-
struction to render them more easy of manipulation and less liable to get out
of repair.
The invention will be fully described with reference to the accompanying
drawings:-
Fig. 1, is a front elevation of the shutter showing the position of the parts at
rest and the shutter closed when set for the highest speed of travel and shortest
exposure say 1 of a second.
Fig. 2, side elevation of Figs. 1 and 5.
Fig. 3, is a front elevation of the operative parts as in Fig. 1 showing the
position of same when moved to set the shutter for exposure and in readiness for
release.
Fig. 4, is a front elevation of setting and releasing mechanism showing position
of the releasing levers when depressed.
Fig. 5, is a front elevation of the shutter showing the position of the parts at
rest and the shutter closed when set for the slowest speed of travel and longest
exposure say one second.
Fig. 6, is a front elevation of the operative parts as in Fig. 5 showing position
of same when moved to set the shutter for exposure and in readiness for release.

page_text: Fig. 7, is a front elevation of the shutter leaves and connecting levers and
spring when closed as in Figs. 1 and 5.
Fig. 8, is a front elevation of operating spring showing position taken by it
when the shutter is set for exposure as in Figs. 3 and 6 the leaves remaining
closed as in Fig. 7.
Fig. 9, is a front elevation showing position of shutter leaves when full open
during exposure and connecting lever and operating spring.
Fig. 10, is a side elevation partly in section of Figs. 9 and 11 showing revolv-
ing disc and also second spring.
rig. 11, is a front elevation (partly in section) showing position of second
spring when set free for exposure as in Figs. 3, 6 and 8.
Fig. 12, is a front elevation of iris diaphragm when open or presenting largest
aperture.
Fig. 13, is a transverse section of Fig. 12.
Fig. 14, is a back or reverse view of plate C which operates the leaves A of
the diaphragm in same position as in Fig. 12.
Fig. 15, is a front elevation showing position of the leaves A of diaphragm
when closed or presenting smallest aperture.
Fig. 16, is a back or reverse view of operating plate C in same position as in
Fig. 15.
Fig. 17, is a back or reverse view enlarged detail showing one leaf of dia-
phragm with hooked pivot 6 of carrier plate B.
Fig. 18, is a transverse section of Fig. 17.
The iris diaphragm (more particularly shown in Figs. 13 to 18) is constructed
with a number of leaves A of the usual shape pivoted to or carried by a carrier
or base plate B. The base plate B is constructed from thin sheet metal with a
number of small tongues or hooks b of semi-circular or other suitable shape
punched or stamped out to project at one side and form pivots for the leaves A
to move upon. It is also recessed or dished to enclose the leaves A the flange bl
also serving to strengthen or stiffen it.
b
The leaves A are each stamped with a hole a at one end to fit upon the pivots
formed by the tongues 6 stamped out of the plate B and are each fitted with a
pin or projecting piece a¹ to fit into and engage with the slots c formed in the
slotted operating plate C.
The slotted operating plate C is also stamped from thin sheet metal with the
requisite number of slots c to correspond with the number of the diaphragm
leaves A and engage with the pins or projections a' thereon. The slotted operat-
ing plate C is preferably caused to move or rotate by a lever c¹ projecting there-
from the carrier plate B being preferably stationary. The slotted plate may
however be held stationary and the carrier plate B be caused to rotate, the
action in the two cases being precisely similar.
The shutter leaves or blades D are of the usual shape shown in Figs. 7, 9
and 10 stamped from thin sheet metal vulcanite or other material and they and
the diaphragm leaves A and plates B and C are encased in the same case or
cover H both being situated between the glasses which form the members of the
lens.
The operating disc E by which the shutter leaves or blades are actuated has
fitted to it a pinion e and is rotated by a quadrant F working on a pivot f in the
side of the case H. The quadrant is provided with a lever or extension f¹
by which it is moved upon its pivot f to rotate the disc E. This lever f¹ is so
placed as to balance in appearance the auxiliary releasing lever G¹ pivoted on
the other side of the shutter.
The operating disc E is provided on its periphery with two pins or projec-
tions e with which the end of the releasing lever G engages to hold it stationary
5 when set.
To the operating disc E are attached two springs K and L (see Figs. 7 to 10)

page_text: one of which rotates it back to its position of rest and the other actuates the
shutter leaves D. The spring at one end is attached to a fixed pin or stud k
in the casing H and at the other end to a stud or pin affixed to the disc E so that
when the disc is rotated by the quadrant I to set the shutter the spring is
extended as shown in Fig. 11. When the disc is released the spring returns it
to the position of rest (see Figs. 1 and 5). The second spring L is at one end
attached to the lever which actuates the shutter leaves D. and at the other to
the pin or stud k¹ on the operating disc so that when the disc E is rotated by
the quadrant F to set the shutter the spring is extended and drawn into the
position shown in Fig. 8 the shoulder on the end of the lever d at the same time
catching behind the pin k¹.
The leaves D are hung upon the two pivoted levers (pivoted upon the
pins and the top of one leaf being pivoted to the top ends of both levers
and the bottom of the other leaf pivoted to the bottom ends of both levers there-
by giving a simultaneous opposite and parallel movement to the two leaves D
forming the shutter. The lever d is pivoted to the lever and is drawn up or
forward into the position shown in Fig. 7 by the spring L to close the aperture
in the shutter leaves 1). The setting of the disc E draws the pink forward behind
the shoulder or notch at the end of the lever and on the release of the disc
the lever is carried by the pin into the position shown in Fig. 9 the pin
slides past the lever and it is drawn back by the spring L into the position
shown in Fig. 7 again closing the shutter.
The releasing lever G is pivoted to the side of the case H on the pin gl and its
end engages the pin or perforation el on the periphery of the rotary operating
dise E to hold it when the shutter is set and with the pin when it is desired to
arrest the travel of the shutter blades and hold them open for any required
length of time. It is moved by the pneumatic plunger N to the end of which at n
a tube is attached. The releasing lever G may also be moved by the auxiliary
lever Gone end of which engages with the pin g..
The speed of movement of the shutter leaves or blades 1) is controlled by a
pneumatic plunger and casing which are connected to the rotating operating
dise E. The lever P by which the pneumatic timing device () is connected to
the disc E is pivoted upon a movable fulcrum R carried at one end of the pivoted
lever S which can be readily moved to change the position of the pivot or ful-
crum R of the lever P. The connecting lever l' is connected by a short link T
with the rotating setting or operating disc E the link T being pivoted to the
lever P by a pin or pivot and to the disc by a pin or pivot . When set in
position to work the shutter at its fastest speed the fulcrum is so placed that
the pivot t by which the link T is attached to the connecting lever P is coincident
or concentric with the centre of the disc E so that the rotary movement of the
disc does not move the lever. The alteration or raising of the fulcrum R by the
movement of the pivoted lever S lifts the pivot t eccentric to the disc E whereby
the rotation of the dise during setting draws the end of the lever P connected
to the pneumatic timer 0 away from it, from the position shown in Fig. 5 to that
shown in Fig. 6 thereby lengthening the travel of the pneumatic case o over the
plunger consequently correspondingly retarding the rotation of the disc E and
the closing movement of the shutter leaves D thereby lengthening the time of
exposure.
When the disc E is working slowly the releasing lever G engages the second
pin or stop on the periphery when the aperture in the shutter leaves is wide
open and may be so retained for a time exposure for any desired length of time
the shutter closing when the releasing lever is a second time operated.
The lever S carrying the movable fulcrum R is provided with an index
finger at the opposite end moving in a slot in the casing H over an index
plate affixed thereto. By moving the free end of the lever with the finger r
the position of the fulcrum R is changed and the speed of exposure adjusted.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is:
-
1. In a photographic shutter the combination with the shutter leaves 1 and
the rotation disc E for operating the same of the pinion e attached to the disc
the pivoted quadrant F for rotating the same and the pivoted lever G to release
the disc substantially as described.
2. A pneumatic shutter constructed with a rotating disc to operate the shutter
connected to a pneumatic timing device such as O by a connecting lever pivoted
upon a movable fulcrum and a link pivoted to the disc so that the movement of
the fulcrum brings the end of the link to or from the centre of rotation sub-
stantially as and for the purpose described.
3. The combination with a rotary disc for operating the shutter of the pneu-
matic timer Ŭ connected to the disc by a lever P mounted upon a movable
fulcrum, the connecting lever P, a lever carrying the movable fulcrum and the
link T pivoted to the lever l' and to the disc substantially as described.
4. An iris diaphragm for pneumatic shutters constructed with a carrier plate
provided with tongues stamped out to form pivots for the diaphragm leaves,
the diaphragm leaves pivoted thereto provided with projecting pins and the
actuating 'plate with slots stamped therein to move the leaves to and from the
centre substantially as described.
5. A photographic shutter constructed with the several parts arranged in com-
bination substantially as described and shown with reference to Figs. 1 to 11
of the drawings.
6. An iris diaphragm for photographic shutter constructed and arranged sub-
stantially as described and shown with reference to Figs. 12 to 18 of the drawings.
Datad this 3rd day of August 1900.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, London, & Birmingham,
Patent Agents.