IMPROVEMENTS IN ARMOUR PLATES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in the
County of Middlesex Gentleman for an Invention of "IMPROVEMENTS IN
ARMOUR PLATES " Communicated to him from Messieurs Marrel Brothers
persons rosident at Rive de Gier in the Republic of France
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 21st December 1882.
46
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman IMPROVEMENTS IN ARMOUR PLATES" a communication to me from
Messieurs Marrel Brothers persons resident at Rive de Gier in the Republic of
France
The manufacture of Armour plates with steel of uniform quality throughout
presents disadvantages arising from the nature of the metal that is to say when a
plate is made of soft steel it is liable to be penetrated by a projectile in a similar
manner to a plate of iron but is more liable to fly or crack than the latter whilst
a plate of hard steel presents the opposite defect being impenetrable but liable to
break under the impact of projectilos
It is the object of this present Invention to remedy these defects by casting two
qualities of steel in one and the same mould so that one part of the plate consists
of hard steel and the other part of soft steel. In order to accomplish this object
ladles or crucibles of the different qualities of steel are melted and brought to the
inould simultaneously. To prevent the two qualities of steel from mixing together
in the mould a. plate of sheet iron or steel is introduced into the mould so as to
divide the latter into two compartments and the hard steel which is to form one
side of the improved armour plate is poured into one of these compartments at the
same time that the soft steel forming the opposite side of the said plate is poured
into the other compartment-The division plate may be heated to a welding heat
before the casting or cold plates may be employed. In the former case the division
plate should be of such a thickness as not to be liable to be penetrated by the
inolten steel but when cold plates are employed the said plates should be so thin as
to enable the heat of the steel to raise it to the temperature requisite to effect
welding.
By a similar process armour plates may be produced presenting two thicknesses
of steel and one thickness of irou-In this case the iron is introduced into the
mould in a similar manner to the division plate hereinbefore described and the
steel cast on either side of it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the
19th June 1883.
"
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN ARMOUR PLATES a communication to me from
Messieurs Marrel Brothers persons resident at Rivo de Gier in the Republic of
France.
The manufacture of Armour plates with steel of uniform quality throughout the
entire thickness of the plate presents disadvantages arising from the nature of the
metal, that is to say when a plate is made of soft steel throughout it is liable to be
ponetrated by a projectile in a similar manner to a plate of iron but is more liable
to fly or crack than the latter, whilst a plate made entirely of hard steel presents
the opposite defect being impenetrable but liable to break under the impact of
projectiles
It is the object of this present Invention to remedy these defects by casting two
qualities of steel in one and the same mould so that one part of the plato consists
of hard steel and the other part of soft steel. In order to accomplish this object the
different qualities of steel are melted and brought to the mould simultaneously but
in separate ladles or crucibles and to prevent the two qualities of liquid steel from
mixing together in the mould a plate of iron or steel is introduced into the mould
so to divide the latter into two compartments and the hard steel which is to form
one side of the improved armour plate is poured into one of these compartments at
the same time that the soft steel forming the opposite side of the said plate la
poured into the other compartment. The division plate may be heated to a
welding heat before casting; or cold plates may be employed. In the former case
the division plate should be of such a thickness as not to be liable to be penetrated
by the molten steel but when cold plates are employed the said plates should be so
thin as to enable the heat of the steel to raise it to the temperature requisite to
effect the welding or union.
By a similar process armour plates may be produced presenting two thicknesses
of steel and one thickness of iron as hereinafter described.
In this case the iron is introduced into the mould in a similar manner to the
division plate hereinbefore described and the steel cast on either side of it.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the
several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figures 1 and 2 are sections at right angles to each other of a mould arranged
for casting armour plates according to this Invention.
Figure 3 is a transverse section of an improved armour plate composed of one
thickness of iron and two thicknesses of steel.
Referring to figures 1 and 2, A is an ingot mould of suitable construction into
which is introduced a relatively thin plate B of iron or steel dividing the interior
of the mould A into two compartments marked respectively C and D. The soft
steel being brought to the mould in a suitable ladle or crucible is poured into the
compartment Cat the same time that the hard steel is poured into the com-
partment D from another ladle or crucible so that the two qualities of steel are
welded at the division B which is either previously heated or is so thin as to readily
acquire the temperature of the adjacent molten steel as herein before described
In the armour plato illustrated in Figure 3 a division plate B¹ is employed of

page_text: such thickness as to form a relatively important section of the finished plate and
obviously must be at a welding heat at the time when the steel is run into the
mould to form the two thicknesses marked respectively C and D' Figure 3.
Having now described and particularly ascertained the nature of the 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 hereinbefore in part
recited Letters Patent is:-
The improved armour plates presenting steel surfaces of different degrees of
hardness and tenacity on opposite sides of the said plate obtained by casting
different qualities of steel on opposite sides of a division plate arranged inside the
mould substantially as hereinbefore described.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this fifteenth day of June One thousand
eight hundred and eighty three