Improved Photographic Shutter.
Year: 1889

page_text: Date of Application, 10th Sept., 1889
Complete Specification Left, 30th May, 1890-Accepted, 5th July, 1890
Improved Photographic Shutter.
I, HENRI TRUNBERRY, Manufacturer of Photographic Shutters, of 22 Rue de
Bretagne, Paris, in the Republic of France, do hereby declare the nature of this
invention to be as follows
This invention has for its object to provide a new form of shutter for photo-
graphic cameras.
This shutter may be employed at will for effecting instantaneous exposure, or
exposures of which the duration may be regulated as desired. It is actuated by
a compressed air piston, through an india rubber tube terminating in a pear or
ball as usual.
The piston alternately moves two slides which constitute the shutter apparatus
properly so called, from top to bottom, and which in sliding vertically one in front
of the other, alternately open and close the objective opening of the apparatus.
The two slides are respectively actuated one by the other, each of them being
provided on its side with a rack, the teeth of each of which engage at the same
time with a pinion common to both, and which turns freely on its axis under
the impulse given by either one of the said slides, when itself actuated by the
piston.
It will be understood that no matter which of the said slides is caused to move
upwards by the piston, its movement in that direction, at the same time, through
the action of the common pinion, imparts the opposite movement that is to say
the downward movement-to the other slide. They therefore slide one over the
other, and thus in succession produce the opening and closing of the objective
opening. The alternate action of the piston upon the two slides is regulated by
two springs in the form of elongated arcs, which alternately force the said piston
under each of the slides. These two slides, in descending and rising, themselves
counteract the said springs and render them free in succession.
The above description applies to what is called instantaneous exposure.
For exposures of varying duration the travel of the slides is controlled to a
given extent. Such limitation is effected by means of a bolt which arrests the
upward movement of one of them, and through the downward movement of the
other slide, the action of the one being governed by the other, as above described.
This bolt is actuated in a horizontal direction by a pin cut off slantingly, and
which enters vertically a transverse slot formed in the said bolt, and which is
also made slanting. An opposing spring placed in the bottom of the socket
or box in which the bolt is confined, pushes it automatically each time the pin in
rising renders it free. This pin and the slot which it enters in the bolt, are
correspondingly inclined, as above stated, and slide one over the other with a
gentle friction. It will be understood by this, that when the finger of the operator
presses on the said pin, the latter pushes the bolt which limits the travel of the
two slides, to the bottom of its socket, and at same time compresses the opposing
spring. When on the contrary the finger is withdrawn, the opposing spring by
expanding then forces the bolt in the direction of the slides, and causes the pin
to itself rise to its position of rest. In the latter position the shutter is adapted
for what is known as varying exposure, the duration being, as it is easy to under-
stand, regulated by the operator, by means of the pin already described.
Besides what has been above described, a special arrangement enables the
diameter of the objective opening to be reduced, with the object of enabling
the shutter to be readily adapted to different sized apparatus.
This arrangement consists of a ring which is not entirely closed, and which

page_text: forms the orifice itself, or the inner edge of the opening in the shutter, and
which may be diminished or increased alternately, under the pressure of two
cylinders, screwed one over the other, and between which it is imprisoned. To
produce the effect indicated, the said ring is broken at a point in its circuit, and
its extremities are made so that when being decreased they slide one into the
other. Further, the body of the said ring is triangular in cross section, the apex
thereof being the external edge, while the base is on the contrary the internal
edge of such ring. It will, therefore, be seen that the two cylinders by screwing
one on to the other, lessen the space left between them and within which the
ring for regulating the opening is enclosed, and consequently progressively press
the said ring and drive it towards its centre, thus producing its contraction and
diminution.
The reverse effect will on the contrary be produced by unscrewing the two
cylinders.
Dated this 10th day of September 1880
COMPLETE SPECIFICATION.
Improved Photographic Shutter.
I, HENRI TRUNBERRY, Manufacturer of Photographic Shutters, of 22 Rue de
Bretagne, Paris, in the Republic of France, 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 to provide a new form of shutter for photo-
graphic cameras, which is fully illustrated in the various figures of the accompany-
ing drawing, in which
Fig. 1 is a front elevation of the shutter, the objective opening being open.
Fig. 2 is an elevation of the ring for regulating the objective opening.
Fig. 3 is a horizontal section of such ring, and of the means for actuating same.
Fig. 4 is a front elevation of the shutter with the objective opening closed.
Fig. 5 is a transverse section on the line a, a, Fig. 4, and shows the open and
closed positions.
Fig. 6 is a detail view on a larger scale of the arrangement for controlling the
travel of the slides.
The shutter may be employed at will either for effecting instantaneous exposures,
or exposures of which the duration may be regulated as desired. It is actuated
by a piston f, which imparts movement to a rod i, and is operated by compressed
air from an india-rubber tube terminating in a pear or ball g as usual.
The piston and its rod i actuate alternately from bottom to top the two slides b
and c constituting the shutter apparatus properly so called, and which in sliding
one in front of the other within the casing a, alternately open and close the
objective opening of the apparatus.
The two slides are respectively actuated one by the other, each of them being
provided for this purpose with a rack on its side, the teeth of each of which
engage at the same time with a pinion j common to both, and which turns freely
on its axis, under the impulse given by either one of the said slides, when itself
actuated by the rod i of piston f.
It will be understood that no matter which of the said slides is caused to move
upwards by the piston, its movement in that direction, at the same time, through
the action of the common pinion, imparts the opposite movement-that is to say
the downward movement-to the other slide. They therefore slide one over the
other, and thus in succession produce the opening and closing of the objective
opening. The alternate action of the piston upon the two slides is regulated by
two springs kand 1, in the form of elongated ares, which alternately force the
rod of the said piston under each of the slides, 'These two slides, in descending

page_text: and rising, themselves counteract the said springs and render them free in
succession.
The above description applies to what is called instantaneous exposure.
For exposures of varying duration the travel of the slides is controlled to a
given extent. Such limitation is effected by means of a bolt o, which arrests
the upward movement of one of them, and through it the downward movement
of the other slide, the action of the one being governed by the other, as above
described. This bolt o, which is shown on a larger scale in Fig. 6, is actuated
in a horizontal direction by a pin s cut off slantingly, and which enters
vertically a transverse slot formed in the said bolt o, and which is also made
inclined. A spiral spring placed in the bottom of the socket or box p, in which
the bolt is confined, pushes it automatically each time the pin s in rising renders
it free. This pins and the slot which it enters in the bolt, are correspondingly
inclined, as above stated, and slide one over the other with a gentle friction. It
will be understood by this, that when the finger of the operator presses on the
head of said pin s, the latter pushes the bolt o, which limits the travel of the two
slides, in a horizontal direction to the bottom of its socket, and at same time
compresses the opposing spring g. When on the contrary the finger is with-
drawn, the opposing spring 9 by expanding then forces the bolt in the direction
of the slides, and causes the pins to itself rise to its position of rest. In the latter
position the shutter is adapted for what is known as varying exposure, the duration
being, as will be readily understood, regulated by the operator, by means of the
pin s already described.
Besides what has been already described, a special arrangement, shown in
Figs. 2 and 3, enables the diameter of the objective opening to be reduced at will,
with the object of enabling the shutter to be readily adapted to different sized
apparatus.
This arrangement consists of a ring m which is not entirely closed, and which
forms the orifice itself, or the inner edge of the opening in the shutter, and which
may be diminished or increased alternately, under the pressure of two cylinders d
and d', screwed one over the other, and between which it is imprisoned in a free
space v. To produce the effect indicated, the said ring m is broken at a point in
its circuit, and its extremities are cut away at n in opposite directions, as shown
in Fig. 3, so that when being decreased they slide one into the other. Further;
the body of the said ring is triangular in cross section, the apex thereof being the
external edge, while the base is on the contrary the internal edge of such ring.
It will, therefore, be seen that the two cylinders by screwing one on to the other,
lessen the space left between them and within which the ring m for regulating
the opening is enclosed, and consequently progressively press the said ring and
drive it towards its centre, thus producing its gradual contraction.
The reverse effect will on the contrary be produced by unscrewing the two
cylinders d, d'.
This arrangement, as above stated, enables the shutter to be applied to photographic
apparatus of different sizes.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The method of operating the two slides by means of two racks with which they
are provided, of a common pinion placed between the two racks, the teeth of each of
which engage the pinion at the same time, and of a compressed air piston with a rod
which passes alternately ander each of the slides, under the alternate action of two
springs in the form of elongated ares, substantially as specified.
2. The method which permits of the production at will of either instantaneous
exposure or varying exposure, by means of a bolt actuated horizontally and regulated
both by an opposing spring operating automatically and situated in the bottom of
its socket or box, and by a pin cut off slantingly and actuated by the operator,

page_text: and which enters a recess also of inclined form in such bolt, substantially as
specified.
3. The system whereby the diameter of the objective opening may be diminished
or increased at will by means of a ring forming the orifice in the shutter, such ring
being of triangular section and broken at a point in its circuit, and its extremities
being cut away so that they can slide one within the other, the contraction of said
ring being produced by the screwing up of two cylinders between which the ring is
placed, and which cylinders screw one into the other, such screwing up causing
the ring to be driven in towards its centre, all substantially as specified.
Dated this 29th day of May 1890.
ALLISON BROS.,
Agents for the Applicant.