IMPROVEMENTS IN THE MANUFACTURE OF ARMOUR PLATES
Year: 1867

page_text: LETTERS PATENT to Francis Montagu Smith, of; Waltham Abbey, in
the County of Essex, Captain in Her Majesty's Royal Artillery, for the
"
PROVISIONAL SPECIFICATION left by the said Francis Montagu Smith
at the Office of the Commissioners of Patents, with his Petition, on
the 26th October 1867.
I, FRANCIS MONTAGU SMITH, of Waltham Abbey, in the County of Essex,
Captain in Her Majesty's Royal Artillery, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ARMOUR PLATES,"
to be as follows:-
This Invention relates to a peculiar mode of manufacturing armour plates,
and has for its object the obtainment of a more homogeneous and perfectly
welded armour plate than has hitherto been obtainable by the ordinary
process of rolling, whilst at the same time the fibres of the iron are arranged
in the most advantageous position for bulging without cracking under the
impact of shot.
According to my Invention I manufacture armour plates by first producing
cylindrical coils from long bars of wrought iron, taking care that the contact
or superposed surfaces in such coils shall be rounded in lieu of flat, whereby
all the cinder will be effectually expelled during the process of welding.
Having formed a hollow welded coil or cylinder as above described of any

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Francis Montagu Smith in the Great Seal Patent Office
on the 24th April 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
MONTAGU SMITH, of Waltham Abbey, in the County of Essex, Captain in
Her Majesty's Royal Artillery, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of October, in the year of our
Lord One thousand eight hundred and sixty-seven, in the 31st year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Francis Montagu Smith, Her special license that I, the said Francis
Montagu Smith, my executors, administrators, and assigns, or such others as I,
the said Francis Montagu Smith, my executors, administrators, or 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 THE MANUFACTURE OF ARMOUR PLATES," upon the condition
(amongst others) that I, the said Francis Montagu Smith, my executors and
administrators, by an instrument in writing under my hand and seal 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.
NOW KNOW YE, that I, the said Francis Montagu Smith, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, that is to say :—
My said Invention has for its object the construction of non-laminated
thoroughly welded armour plates which shall consist in fact of homogeneous
masses of soft wrought iron, thereby attaining the great desideratum that
under the impact of shot these plates shall bulge with the least possible
amount of cracking.
The ordinary system of manufacture, namely, by piling a number of thin

page_text: plates one over another, heating them in the furnace, and then passing them
between powerful rolls or under the hammer is open to the objection that a
perfect weld between the component layers of plates cannot be guaranteed,
indeed it is practically impossible to ensure sound welding by piling and
rolling together flat plates.
Now according to my Invention I propose to construct an armour plate
out of soft bar iron in such a way that the only wellds shall be between
contiguous convex surfaces so that on welding all "cinder" must necessarily
be expelled. This is to be effected by forming the bar into a single or
double coil similar to those used for Armstrong guns, welding it together as
for a gun, cutting open the cylinder so formed, and flattening it out into the
form of a plate eithe under the hammer or by passing it between rolls. By
using a bar of soft iron and of a proper sectional form absolutely sound welds
may be guaranteed and the resulting plate will therefore be a non-laminated
thoroughly welded homogeneous mass of iron. I prefer to use a softer iron
than that used for gun coils as it is better adapted for armour plates. This
will greatly increase the probability of sound welding and in case a flaw in
welding should occur arising from "blister" or other like cause, such flaw
will only present a short line on the surface of this finished plate and con-
sequently the chances of a pointed shot striking exactly in such a line would
be very small indeed. But provided the adjacent surfaces of the coiled bar
are sufficiently convex there is nothing to prevent a practically sound and
thorough weld being made; by using armour plates manufactured in the
way proposed for compound structures of two or more plates in thickness,
such as shields for land defences, a considerable increase of strength or
resistance may be obtained by placing two plates together in such a way that
their respective lines of welding shall break joint or cross each other. The
iron best adapted for my improved armour plates would be the best and
softest cold blast charcoal iron that can be procured, but good soft iron such
as is used in the manufacture of ordnance will answer if care be taken that
the iron employed contains no trace of phosphorus which would render it
"cold short" and therefore unsuited to withstand the impact of shot.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is, the manufacture of armour
plates from soft bar iron by forming the bar into a single or double coil,
welding such coils together, cutting open longitudinally the cylinder thus

page_text: obtained and flattening it out into the form of a plate substantially as herein-
before described.
In witness whercof I, the said Francis Montagu Smith, have to this
iny Specification set my hand and seal, this Twentieth day of April,
One thousand eight hundred and sixty-eight.
FRANCIS MONTAGU SMITH. (L.S.)
Capt. R. A.
FRANCIS MONTAGU SMITH. (L.S.)
Capt. R. A.