Improvements in or connected with Photographic Shutters.
Year: 1893

page_text: Date of Application, 30th Mar., 1893
Complete Specification Left. 1st Jan., 1894-Accepted, 3rd Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in or connected with Photographic Shutters.
I, CHARLES BELOT, of 3 Rue Foincon, Brussels, in the Kingdom of Belgium,
Photographic Apparatus Manufacturer, do hereby declare the nature of this
invention to be as follows
My invention relates to photographic shutters and comprises an improved
arrangement of lever for operating the shutter proper and of pneumatic chamber,
and means for arresting its movement as soon as the exposure has been effected.
In carrying out my invention I construct the pneumatic chamber of two tubes
arranged to slide one within the other and each being closed at its outer end; to
the inner tube is applied a compressible air ball, the inner tube is provided with
two projecting stops and a spring to which is fixed a bevelled catch.
The inner tube is fixed on a suitable support and the outer tube is attached to
the shutter plate.
A washer provided with a small catch is capable of movement around the axis of
the said support.
The pneumatic chamber is provided with a casing in order to prevent any rays
of light from passing through the shutter.
The pneumatic chamber is usually placed at the back of the shutter allowing
the two stops and the catch of the spring to pass outside. Slides are made in the
plate in order to allow free play for the working of the moveable tube or piston
of the pneumatic chamber.
The lever is mounted upon a pivot and the catch of the spring is placed exactly
in front of a projection or tooth on the lever; when the piston commences to move
by pressure upon its air-ball, it moves the lever until the shutter is completely
open the piston continuing its movement the catch of the spring passes in front of
the said tooth; at the moment one of the stops on the inner tube comes in contact
with another tooth or projection on the lever and pushes back the lever to its former
position thus closing the shutter.
When the pressure upon the air-ball is removed the pneumatic chamber also
resumes its former position, the springs passing beneath the projection without
acting upon it. Owing to the bevelled form of the catch of the spring the other
stop on the inner tube comes in front of a third tooth or projection and prevents
the lever from moving so long as no fresh movement of the piston is produced.
The above description as regards the operation of the apparatus. concerns
instantaneous photography.
When it is desired to keep the shutter open with the object of preventing the
first named stop on the inner tube from coming in contact with the second tooth or
projection on the lever the washer is turned until its catch (as soon as the shutter
is completely opened) strikes against a pin placed at the back of the shutter plate.
The shutter remains open as long as pressure is maintained on the air-ball. When
the pressure is relieved the piston retakes its former position and the catch acting
upon the third tooth or projection of the lever brings back the latter simultaneously
to its initial position.
The lever may be so modified that the second (lower) stop on the inner tube
brings back the lever into place and keeps the shutter closed. It is obvious that
the shutter is as herein before described attached to the lever.
Instead of employing a pneumatic chamber for actuating the operating lever of
the shutter I can use a spring arrangement acting upon a pinion and rack.
To allow of utilizing the same apparatus for a longer exposure I brake the

page_text: lever which actuates the shutter plates by an arrangement consisting essentially of
a semi-circular appliance adapted to the lever and a strip terminated by a small
piece of leather which bears in a variable manner on the semi-circular piece by
means of a threaded stud in a nut fixed to a suitable part of the apparatus.
Dated the 30th day of March 1893.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or connected with Photographic Shutters.
I, CHARLES BELOT, of 3, Rue Foincon, Brussels, in the Kingdom of Belgium, 1
Photographic Apparatus Manufacturer, 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:—
My invention relates to photographic shutters and comprises an improved
arrangement of lever for operating the shutter proper, and of pneumatic chamber,
and means for arresting its movement as soon as the exposure has been effected.
In the accompanying drawing,—
Figure 1 is an elevation of the pneumatic chamber with its support and milled
disc hereinafter described:
Figure 2 is a detached elevation of the support and plan of its spring and
catch:
Figure 3 is a plan of Figure 1:
Figure 4 is a perspective view of the pneumatic chamber with its casing for
preventing the passage of light through the shutter:
Figure 5 is a developed view of the casing and an end view of the milled
disc:
Figure 6 is a detached elevation of the operating lever:
Figure 7 is a similar view of a modified form of the said lever:
Figure 8 is an elevation of a photographic shutter with my improved arrange-
ment of lever and pneumatic chamber applied thereto :
Figures 9 and 10 are elevations illustrating two different positions of the parts:
Figure 11 is an elevation of a modification:
Figure 11 is an elevation of another modification:
Figure 12 is an elevation and an edge view illustrating a brake arrangement for
the lever.
In carrying out my invention as illustrated in Figures 1 to 6 and Figures 8, 9
and 10 I construct the pneumatic chamber of two tubes A, A' arranged to slide
one within the other and each being closed at its outer end; to the inner tube A'
which acts like a piston is applied a compressible air-ball, and this tube is fixed on
a support B provided with two projecting stops b, b' and a spring c to which is fixed
a bevelled catch c'.
The outer tube A is attached to the shutter plate by means of a plate a having
lugs a¹.
A milled disc D is provided having a small lug or projection D₁ and capable of
rotation upon the pin or stud a² that connects the inner tube A' to the support B.
The pneumatic chamber is provided with a casing F, Figures 4 and 5, in order
to prevent any rays of light from passing through the shutter.
The pneumatic chamber A, A¹ is placed as usual at the back of the shutter
allowing the two stops b, and the catch e' of the spring c to pass outside, slots b²,
Figures 8, 9 and 10, being made in the plate for this purpose and in order to
allow free play for the working of the movable tube or piston A¹ of the pneumatic
chamber.

page_text: E, Figures 6, 8, 9 and 10, is the lever for operating the shutter, such lever being
mounted upon a pivot 9 in the shutter and the catch c¹ of the spring e placed
exactly in front of a projection or tooth e on the lever; when the inner cylinder
or piston commences to move by pressure upon the air-ball, it moves the lever E
until the shutter is completely open; the piston continuing its movement the catch c¹
of the spring passes over the said tooth e; at this moment the stop & comes in
contact with another tooth or projection el on the lever E and pushes back the
lever to its former position thus closing the shutter.
When the pressure upon the air-ball is removed the piston A' also resumes its
former position, the spring c passing beneath the projection e without acting upon
it owing to the bevelled form of the catch c' and the stop & comes in front of a
third tooth or projection ell and prevents the lever from moving so long as no further
movement of the piston takes place.
The above description as regards the operation of the apparatus concerns
instantaneous photography.
When it is desired to keep the shutter open the disc D with the object of
preventing the stop from coming in contact with the tooth or projection e¹ on the
lever is turned until its lug D' strikes (when the shutter is completely opened)
against a pin , Figure 8, placed at the back of the shutter-plate. The shutter
remains open as long as pressure maintained on the air-ball. When the pressure
is relieved the piston retakes its former position and the catch e' acting upon the
tooth or projection el of the lever brings back the latter simultaneously to its
initial position.
The lever may be so modified as shewn at E' Figure 7 that the stop 6' brings back
the lever into place and keeps the shutter closed. This lever is attached to the
shutter in the same manner as the lever E, Figure 6.
Instead of employing a pneumatic chamber for actuating the operating lever of
the shutter I can use a spring wound in a barrel and acting by means of a pinion B¹
upon a rack C¹ fixed to the piece B as shewn in Figure 11.
A more simple arrangement, which is, however, merely a modification of that
illustrated in Figure 11, is shewn at Figure 11 bis and consists in substituting for
the rack and pinion a bent lever d fixed on the spindle d' of the spring barrel,
a to-and-fro movement being imparted to the lower part of such lever like that
of the rack and the piece B, Figures 1, 2, 3 and 8, which latter it also replaces,
the said lower part of the lever being provided like the piece B with a spring c and
performing the same functions as this piece.
To allow of utilizing the same apparatus for a longer exposure I brake the
lever E which actuates the shutter plate by an arrangement illustrated in Figure 12
consisting essentially of a semi-circular bar t adapted to the lever E and a spring (2
terminated by a small piece of leather which bears on the semi-circular bar with a
pressure which can be adjusted by means of a threaded stud t' working in a nut
fixed to the plate G of the apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination with a photographic shutter of an oscillating lever such
as E for operating the shutter, which lever is provided with projections or
teeth e, e, el, a catch c¹ carried by the piston of a pneumatic chamber and
acting on the teeth e and e" and stops b and also carried by the said piston
and acting on the teeth ell and e' respectively, substantially in the manner
hereinbefore described with reference to Figures 1, 2, 3, 4, 6, 8, 9 and 10 of the
accompanying drawing.
2. The use in combination with a photographic shutter of the levers illustrated
in Figures 6 and 7 respectively of the accompanying drawing.
3. The combination with the mechanism claimed in the first claiming clause of

page_text: the arrangement illustrated in Figures 4 and 5 for allowing of the exposure of
photographs for any required length of time, substantially as set forth.
4. The modification of the arrangement claimed in Claim 1 in which the piston
illustrated in Figures 1 and 2 is replaced by a spring which, by means of a pinion,
actuates a rack carrying the catch c' and stops b and b', substantially as herein-
before described and illustrated in Figure 11 of the accompanying drawing.
5. The modification of the arrangement claimed in Claim 4 and illustrated in
Figure 11 in which a bent lever is employed in place of a pinion and rack for
actuating the operating lever E, substantially as hereinbefore described with
reference to Figure 11.
6. The combination with the mechanism claimed in Claim 1 of the arrangement
illustrated in Figure 12 of the accompanying drawing for braking the lever when
requiring a longer exposure of the photographs substantially as set forth.
Dated this 1st day of January 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.