An Improvement in Photographic Shutter Apparatus.
Year: 1894

page_text: Date of Application, 13th Apr., 1894-Accepted, 19th May, 1894
[Communicated from abroad by FRED. H. KELLEY, of No. 471, Tremont Street,
Boston, United States of America.]
An Improvement in Photographic Shutter Apparatus.
We, THE EUROPEAN BLAIR CAMERA COMPANY LIMITED, of No. 9 South-
ampton Street, in the County of Middlesex, Manufacturers, 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 :-
Our invention relates to a simple and compact apparatus for working the shutter
of a photographic camera as we shall describe referring to the accompanying
drawings.
Fig. 1 is an external front view,
Fig. 2 is a view of the inside of the cover inverted,
Fig. 3 is a view of the shutter, the cover being removed,
Fig. 4 is a section on X X and
Fig. 5 is a section on Y Y.
A is the casing of circular form having a screw threaded opening a by which it
can be fixed on the lens tube of a camera, and B is a diaphragm disc centred on A
and having through it openings 6 of several different sizes. Part of the side and
bottom of the casing A is cut away at a¹ so that the thumb or finger can reach the
edge of the disc B to turn it partly round, so as to bring one or another of the
diaphragm openings 6 into coincidence with the lens opening. Near the edge of
the disc B there are holes b' one in line with the centre of each diaphragm opening b
and there is fixed to the casing a spring 6' with a point fitted to enter any of the
holes b¹.
When the finger or thumb is applied to turn the disc B the engagement of the
spring in one of the holes 6' causes the operator to feel a little resistance by
which he knows that one of the diaphragm openings b is in line with the lens
opening, but this resistance is not sufficient to prevent him from turning the disc
so as to bring another of the diaphragm openings into line with the lens opening.
The casing A has a cover C with screw threaded lens opening c.
On the outside
of C is pivotted a spring lever D which can be moved as far as permitted by a
slotted hole d, either by the finger applied to its end d', or by the movement of a
plunger in a small cylinder E to the end of which at e a flexible tube can be
attached so that the operator, by squeezing a bulb, can cause the plunger of E to
push back the lever D. From the lever D a stud projects through a curved slot
into the interior of the casing. On the same pivot with the lever D is pivotted a
spring lever F having a stud f projecting from it into the interior of the casing,
this stud meeting the stud d' except when the lever F is pulled down so that a gap
is left between and f.
The lever F is held with certain firmness in the one or the other of its two
positions by a stud from it projecting into the one or other of two shallow holes f¹
in the face of the lever D, but the engagement of the stud in the hole does not
prevent the operator from moving the lever F.
Inside, the cover C has pivotted on it a lever G having a slot 9 and it has also
pivotted on it an elastic wire H having at its one end a knob h which projects
beyond the side of the casing, and having its other end engaged at ' in a hole in a
bent up lip of the lever G.
Where the wire H passes through the side of the casing there is a long slot with
several notches in any of which the wire H can be engaged. On the back of

page_text: the diaphragm disc B is centred the shutter disc K having through it the opening k
shewn in Fig. 3.
A stud g projecting from the shutter K is engaged in the slot
of the lever G,
and on the shutter there are also several projecting pins and k³ which act as
stops in conjunction with the studs d' and f, and there are two tappets kk' which
mect a fixed stop when the shutter K turns to its farthest extent in either
direction. The operator by moving the knob until he engages the wire H in one
or other of the notches 2 or 3 bends the wire H between its pivot and its end h¹
and thus puts on the lever G a strain tending to turn it, but as the stud g' is
engaged in the slot of G, and as the shutter disc K is stopped by one of the pins k²
bearing against, there is no movement until the operator by moving the lever D,
either by the finger applied to d¹ or by pneumatically forcing out the plunger of E,
withdraws the studs d2 and f from the path of the pin and thereupon the
wire Hunbending causes the shutter disc K to turn rapidly until it is stopped by
the pink, coming against fits opening k being then brought into coincidence with
the lens opening of the diaphragm. Then, on releasing the lever D the studs
and pass between the two pins holding the shutter disc in position. When it is
desired to close the lens opening, the lever D is again pulled back releasing the
studs d and from between the pins whereupon the shutter disc completes its
stroke moving its opening k away from the lens opening.
When a very rapid, approximately instantaneous, opening and closing of the lens
opening is desired, the lever F is pulled removing the stud f from d' so that when
the lever D is moved, f is beyond the path of the pin and consequently the
shutter disc, instead of stopping in an intermediate position with its opening & over
the lens opening, makes its full stroke, opening for an instant and then closing
the lens aperture. The wire H may be more or less strained by engaging it in one
of the notches nearer to or farther from the end of the slot, the greater or less
rapidity of the movement of the shutter being thus determined.
It is to be understood that having effected one complete movement of the shutter
disc K by engaging the wire H in one of the notches the next movement of the
shutter, which is a return movement, is effected by engaging H in one of the other
notches h³.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what
we claim is:-
1. Photographic shutter apparatus substantially as described with reference to
the accompanying drawings.
2. In apparatus such as is above referred to, the combination of the elastic
wire H the slotted lever G and the stud g' of the shutter disc K arranged and
operating substantially as described.
3. The combination of the spring lever D its stud d, the spring lever F, its
stud and the pins and on the shutter disc K, substantially as described.
4. In combination with the lateral slot a¹ of the casing the diaphragm disc B, its
holes and the spring 3, substantially as described.
Dated this 13th day of April 1894.
ABEL & IMRAY,
Agents for the Applicant.