IMPROVEMENTS IN DIAPHRAGMS FOR OPTICAL INSTRUMENTS
Year: 1858

page_text: LETTERS PATENT to Pierre Maugey, of Paris, in the Empire of France,
Optician, for the Invention of "IMPROVEMENTS IN DIAPHRAGMS FOR OPTICAL
INSTRUMENTS."-Partly a communication.
Sealed the 19th October 1858, and dated the 22nd April 1858.
PROVISIONAL SPECIFICATION left by the said Pierre Maugey at the
Office of the Commissioners of Patents, with his Petition, on the
22nd April 1858.
I, PIERRE MAUGEY, of Paris, in the Empire of France, Optician, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN DIAPHRAGMS
FOR OPTICAL INSTRUMENTS," to be as follows:-
This Invention of improvements in diaphragms for optical instruments
relates to a mode of constructing diaphragms, whereby the size of the aperture
may be regulated at pleasure to the greatest nicety.
This object is effected by making the diaphragm of some elastic material
which is capable of being expanded or stretched.
The material which is preferred is a disc or sheet of india-rubber, or some
other analogous elastic material. A small central circular opening is made in
this disc, the edges of which are securely held or clamped, and by forcing the
disc outwards by means of any convenient instrument, so as to stretch the
material, the central opening or aperture therein will be expanded, or by
drawing back the stretching instrument the aperture will be contracted; the
stretching instrument may be actuated by means of a rack and pinion motion,
which is the most convenient contrivance for the purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Pierre Maugey in the Great Seal Patent Office on the
20th October 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PIERRE
MAUGEY, of Paris, in the Empire of France, Optician, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of April, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Pierre Maugey, Her special license that I, the said Pierre Maugey, my
executors, administrators, and assigns, or such others as I, the said Pierre
Maugey,.my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN DIAPHRAGMS
FOR OPTICAL INSTRUMENTS," being partly a communication from a foreigner
residing abroad, upon the condition (amongst others) that I, the said Pierre
Maugey, by an instrument in writing under my hand and seal, should par-
ticularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Pierre Maugey, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed, and to the
letters and figures marked thereon (that is to say) :
--
This Invention of "Improvements in Diaphragms for Optical Instruments,"
relates to a mode of constructing diaphragms, whereby the size of the aperture
may be increased or diminished, or regulated at pleasure to the greatest nicety.
This object is effected by making the diaphragm of some elastic material,
which is capable of being expanded or stretched. The material which is
preferred is a disc or sheet of india-rubber, either vulcanized or in its natural
state, or some other analogous elastic material. A small central circular
opening is made in this disc, the edges of which are securely held or clamped,
and by forcing the disc outwards by means of any convenient instrument, so
as to stretch the material, the central opening or aperture made therein will

page_text: be expanded; or by drawing back the stretching instrument the aperture will
be contracted.
The stretching instrument may be actuated by means of a rack and pinion
motion, which is the most convenient contrivance for the purpose, but other
means may be employed for effecting the object, if preferred.
The several Figures in the Drawing represent some of the various parts of
an improved diaphragm head constructed according to my Invention.
Fig. 1 is an external side elevation of the diaphragm apparatus complete,
and ready to be adapted to a camera; Fig. 2 is a front view, shewing the
aperture in the elastic diaphragm. A is the outer cylinder which encloses the
various parts of my improved diaphragm, and is shewn detached in section at
Fig. 3, in which it will be seen that the part A is provided in front with a
conically shaped projecting tube B, whereby the elastic diaphragm is stretched,
as will be hereafter explained. This projecting part B of the cylinder A may
be denominated the stretching instrument, and is inserted in another tube C, C,
shewn detached in section at Fig. 4. The front part of the tube C is cut
away at three different places, leaving three projecting pieces C, which are
passed through slots made in the cylinder A, as shewn at a, a, in Fig. 3.
When the tube C is placed in the cylinder A, a ring D is fastened on to the
pieces C* by means of screws or otherwise, as shewn in Fig. 1. This ring is
provided internally with a flange d, as shewn in the detached sectional view,
Fig. 5, and on this flange is placed a thin circular disc of vulcanized india-
rubber, or other suitable elastic substance E (Figures 2 and 5). An aperture
is made in the centre of this disc, which is held down in its seat by its edges
by means of a washer and the ring F, which is screwed into the ring D, as
shewn in Fig. 5. The rear end of the tube C, Fig. 4, is screwed and adapted
to a cylinder G, which is provided with a milled rim H, and when the parts
are put together, the rear end of the inner part of the cylinder A will project
beyond this rim, and will receive a ring I, shewn detached in Fig. 6. This
ring I is secured to the cylinder A by screws or otherwise, and is screwed
externally and internally for the convenience of adapting the improved
diaphragm to the head of a camera.
It will now be understood that the projecting conical part B of the cylinder
A is made to bear against the back of the elastic diaphragm E, and therefore
by pressing or pushing forward this part B against the diaphragm which is
held fast at its outer edge by the flange and ring d and F, the material of
which the diaphragm is composed will be stretched, and in so doing the
central opening or aperture therein will be gradually enlarged, and as it is
proposed to effect the motion of the stretching instrument B by mechanical

page_text: means, the enlargement or contraction of the opening in the diaphragm may
be regulated with the greatest nicety.
Figures 7 and 8 represent one means of actuating the stretching instrument
or piece B, but other plans may be employed, or the piece may be moved
simply by hand, as is well understood.
Having now described this Invention of "Improvements in Diaphragms for
Optical Instruments," and having explained the manner I prefer of carrying
the same into effect, I would observe that I do not mean to confine myself to
the precise arrangement and construction of parts herein shewn and described,
as they may be varied without departing from the nature and object of the
Invention; nor do I mean to restrict myself to the use of vulcanized india-
rubber for making the elastic diaphragms, as other materials or combinations
of materials or ingredients may perhaps be obtained and found to answer the
purpose. In conclusion, I claim as the Invention secured to me by Letters
Patent as aforesaid, constructing diaphragms for optical instruments of an
elastic material, as above described. I also claim the mode herein set forth
of operating upon the elastic diaphragm, whereby the aperture or opening
therein may be altered and regulated at pleasure, as above described.
In witness whereof, I, the said Pierre Maugey, have hereunto set my
hand and seal, the Twelfth day of October, in the year of our Lord
One thousand eight hundred and fifty-eight.
PIERRE MAUGEY, Ainé, (L.S.)
Opticien, Quai Napoléon, 27,
a Paris.