IMPROVEMENTS IN PORTS AND APPARATUS FOR OPENING AND CLOSING THE PORTHOLES OF SHIPS OF WAR, WHICH ARE ALSO APPLICABLE TO EMBRASURES OF FORTIFICATIONS."
Year: 1861

page_text: LETTERS PATENT to Charles Burn, of Delahay Street, Westminster,
Civil Engineer, for the Invention of "IMPROVEMENTS IN PORTS AND
APPARATUS FOR OPENING AND CLOSING THE PORTHOLES OF SHIPS OF WAR,
WHICH ARE ALSO APPLICABLE TO EMBRASURES OF FORTIFICATIONS."
PROVISIONAL SPECIFICATION left by the said Charles Burn at the
Office of the Commissioners of Patents, with his Petition, on the
5th April 1861.
I, CHARLES BURN, of 2, Delahay Street, Westminster, Civil Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN PORTS
AND APPARATUS POR OPENING AND CLOSING THE PORTHOLES OF SHIPS OF WAB, WHICH
ARE ALSO APPLICABLE TO EMBRASURES OF FORTIFICATIONS," to be as follows:-
The object of this Invention is to obtain greater facility for opening and
closing the doors of portholes of ships of war when in action, so that they can
be opened with ease and rapidity when it is intended to fire the gun, and be
closed immediately the gun is fired, and thus prevents shot, shell, or other
missiles from entering the ship through the portholes.
Another object of the Invention is to construct the port doors of sufficient
strength and of such a form and manner that shot, shell, or other missiles
cannot break or penetrate them.
To effect these purposes I cover the porthole by means of two iron, doors
one above the other, the top one closing the top half of the porthole, and the

page_text: bottom one the bottom half, abutting against each other when closed at the
middle of the porthole; these doors move up and down between guides fixed
to the sides of the ship. The upper door is hung on chains, which pass over
two sheaves or pulleys to the lower door, to which they are fastened. By this
means the weight of one door balances the other, and move simultaneously.
The doors may be opened or closed by a direct downward pressure or upward
pull from a handle or horizontal bar fixed to the lower door, or they may be
raised and lowered by means of levers or other suitable contrivance. To offer
the greatest resistance to shot, shell, or other missiles, the doors are made of
hammered iron or steel, and when closed form a diamond-shaped surface,
presenting four angular faces.
SPECIFICATION in pursuance of the conditions of, the Letters Patent, filed
by the said Charles Burn in the Great Seal Patent Office on the
5th October 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
BURN, of Delahay Street, Westminster, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of April, in the year of our Lord
One thousand eight. hundred and sixty-one, in the twenty-fourth year of
Her reign, did, for Herself, Her heirs and successors, give. and grant unto
me, the said Charles Burn, Her special licence that I, the said Charles
Burn, my executors, administrators, and assigns, or such others as I,
the said Charles Burn, 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 "IM-
PROVEMENTS IN PORTS AND APPARATUS. FOR OPENING AND CLOSING THE PORTHOLES OF
SHIPS OF WAR, WHICH ARE ALSO APPLICABLE TO EMBRASURES OF FORTIFICATIONS,"
upon the condition (amongst others) that I, the said Charles. Burn, my
executors or administrators, by an instrument in writing under my, or 'their,
or one of their hands and seals, should particularly 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.

page_text: NOW KNOW. YE, that I, the said Charles Burn, do hereby declare-
the nature of my 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:
The object of this. Invention is to obtain greater facility for opening and
closing the doors of portholes of ships of war when in 'action, so that they can
be opened with ease and rapidity when it is intended to fire the gun, and be
closed immediately the gun is fired, and thus prevent shot, shell, or other
missiles from entering the ship through the portholes.
Another object of this Invention is to construct the port doors of sufficient
strength and of such a form and manner that shot, shell, or other missiles
cannot break or penetrate them.
To effect these purposes I cover the porthole by means of two iron doors,
one above the other, the top one closing the top half of the porthole, and the
bottom one the bottom half, abutting against each other when closed at the
middle of the porthole; these doors move up and down between guides fixed
to the sides of the ship. The upper door is hung on chains which pass over
two sheaves or pulleys to the lower door, to which they are fastened. By this
means the weight of one door balances the other, and move simultaneously.
The doors may be opened or closed by a direct downward pressure or upward
pull from a handle or horizontal bar fixed to the lower door; or they may be
raised and lowered by means of levers or other suitable contrivance. To offer
the greatest resistance to shot, shell, or other missiles the doors are made of
hammered iron or steel, and when closed form. a diamond-shaped surface
presenting four angular faces.
..
Having now described the nature of my Invention, I will now shew
how the same may be carried into practical effect, reference being made to
the accompanying Drawings, in which the same letters of reference indicate
like parts.
DESCRIPTION OF THE DRAWINGS.
Sheets. 1 & 2 Fig. 1 represents a front elevation of a porthole, showing
the ports closed; Fig. 2 represents a front elevation of a porthole, showing the
ports open; Fig. 3 represents vertical section through line C, D, in Fig. 1 ;
Fig. 4 represents vertical section through line Y, Z, in Fig. 2; Fig. 5
représents a horizontal section through line A, B; Fig. 6 represents a
horizontal section through line X, Y; Fig. 7 represents a horizontal section
through line E, F.
P, Fig. 1, represents the top door closing the upper half of porthole, and

page_text: P3 is the other door, which closes the lower half of the porthole, and when'
closed abut against each other, as shewn in Fig. 1 at the middle of the
porthole. These doors move up and down between two iron slides G, which
are fixed or bolted too or against the side of a ship, or when applied to the
embrasures of land fortifications they are built in the masonry. The slides
for the doors are made in the form as shewn in Fig. 6 and 7, and are slightly
larger than the port doors that they move freely therein. In order to give
sufficient strength to the slides at the part facing the porthole to withstand
the blows of shot against the port doors when closed, I make them of greater
thickness, as shewn in Fig. 5; I also face the top or bottom sides of the
porthole with iron plates about two inches thick, to which are screwed the
iron slide, so that the four sides of the porthole form a strong inner framing.
Fixed to the lower door P is an ear or lug H, and to this ear or lug is
attached a chain, which passes outside of the slide over a sheave J, and is
attached to the upper port door P¹, and by this means the weight of the upper
door is counterbalanced by the lower one. Supposing the doors to be shut, as
shewn in Fig. 1, they are opened in the following manner :-Four iron rope
pulleys are fastened to the sides of the porthole at K, K, Figs. 3, 4, and 5;
two are fixed to the top of the porthole, and two at the bottom; a rope passes
over the upper pulley, and is attached to the upper port at L, and another
rope passing under the lower pulley is also attached to the upper port at L.
Upon pulling the top rope M, the doors are opened, and on pulling the lower
rope N the doors are closed, or by making the upper door slightly heavier
than, the lower one, the doors will be self-acting, and close of themselves, as
the weight of the upper door will raise the lower door; in this case only one
rope and one set of pulleys would be necessary.
As in most cases the doors need not be entirely opened to fire the gun, a
modification of the above plan may be made, shewn in Sheet 2, Figures 8, 9,
.and 10. In this case the porthole is closed by four doors, two R', S', closing
the upper half, and two others R², S², closing the lower half. These doors
slide in the frame T. The two doors R', R, are attached to each other by
chains, which pass over two pulleys counterbalancing each other in the
manner herein-before described, and the two doors S¹, S³, and also arranged
in the same manner, therefore when it is unnecessary to open the entire
porthole, the door R' is raised, and the door R³ is lowered to the position as
shewn in Fig. 9, thus opening only one half; and to open the entire porthole
the doors R¹ and S' are raised, and the doors R³ and S lowered to the
position shewn in Fig. 10. These doors may be opened and shut by a direct
motion up and down by means of a lever or handle attached to the lower

page_text: door R'; or they may be raised and lowered by means of a rope and pulley in
the manner herein-before described.
Having now described the manner of carrying the Invention into practical
effect, I wish it to be understood that I do not bind myself to the precise
details, neither as to the size or form of the doors mentioned, nor dimensions
of any of the parts, nor as to the manner of opening or shutting the ports, as
that may be accomplished by various mechanical contrivances, nor as to the
situation of the doors and slide frames, as that will depend upon the con-
struction of the ships or embrasures of land fortifications to what such ports
may be adapted; but what I claim as my Invention is opening and closing
the ports of ships of war or embrasures of land fortifications by means of doors
which move vertically in a slide frame, and arranging the same in the manner
herein-before described, and shewn in the Drawings, that they may counter-
balance each other.
In witness whereof, I, the said Charles Burn, have hereunto set my
hand and seal, this Fifth day of October, in the year of our Lord
One thousand eight hundred and sixty-one.
Witness,
JOSEPH WILLCOCK, Patent Agent, &c.,
89, Chancery Lane,
London.
(L.8.) CHARLES BURN.