Improvements in Armour Plates and Projectiles and in the Manufacture of the same.
Year: 1893

page_text: Date of Application, 17th Feb., 1893-Accepted, 22nd Apr., 1893
COMPLETE SPECIFICATION.
Improvements in Armour Plates and Projectiles and in the
Manufacture of the same.
I, FRANCIS GORDON BATES of No. 2027 North College Avenue in the City
of Philadelphia State of Pennsylvania United States of America Mechanical
Engineer do hereby declare the nature of my invention and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement :-
The object of my invention is to make an armour plate or projectile having an
extremely hard outer surface which, in the case of an armour plate, will render
the plate strongly resistant, and in the case of a projectile will give it great
penetrating quality the said hard outer surface being combined with a softer and
tougher body, core or heart, which will lessen the liability of the plate or projectile
to crack when subjected to sudden shock.
This object I attain in the manner hereinafter set forth, reference being had to
the accompanying drawing, in which
Figure 1 represents a sectional view of an armour plate made in accordance with
my invention.
Figure 2 is a sectional view of a hollow projectile embodying my invention;
Figure 3 is a sectional view of a modified form of the armour plate;
Figures 4 and 5 are sectional views of other forms of hollow projectile ; and
Figures 6 and 7, are sectional views of solid projectiles embodying my invention.
In carrying out my invention the armour plate or projectile is first made of
wrought iron, low steel, or even in some cases of cast iron, and it is then subjected
to a converting operation such for instance as that set forth in the Specification
of Letters Patent No. 7820 dated 20th May, 1890 granted to me, whereby the
iron or low steel is converted into a high grade steel capable of being hardened
and tempered.
If the plate or projectile be in the first instance, of cast iron, it is converted
throughout, but if it be made originally of wrought iron or low steel, it need be
converted only on its opposite surfaces, for instance, upon the front and rear sides
of the armour plate, as shewn in Figure 1, or upon the outside and inside of a hollow
projectile as shewn in Figure 2 or the plate or projectile may be converted only
in that portion which is to receive the shock, for instance in the front portion of
the plate, as shewn in Figure 3, on the outside or point of a hollow projectile, as
shewn respectively in Figures 4 and 5, or upon the outside or point of a solid
projectile as shewn respectively in Figures 6 and 7.
The partial conversion of the plate may be effected by embedding in sand that
portion of the same which is not to be acted upon and surrounding with or placing
against the other portion the converting compound or matter and then subjecting
the whole to heat for the proper length of time, or the plate may be entirely
surrounded by the compound and the converting operation be continued only for
such length of time as may be necessary to convert the outer portion of said
plate, leaving the inner portion or heart in its original condition of wrought iron
or low steel, and either of these plans may also be adopted in converting the
surface or surfaces of the projectile.
The converted portions are then subjected to a tempering or hardening operation
and in the case of a plate or projectile having a heart or core of iron or low
steel between the front and rear or the inner and outer converted portions, the
rear or inner converted portion has preferably a lower temper than the front or
outer portion so that while it increases the stiffness of the plate it is not so liable
to fracture as though it had received a higher temper.

page_text: The maintaining of a body of comparatively soft iron or steel adjacent to the
hard resisting surface of a plate or projectile serves as a cushion to prevent the
fracture of said hard resisting surface by blows received or delivered by it, and it
is also of advantage in the operation of tempering or hardening the surface as it
prevents the formation of cracks or other defects or weaknesses in the said surface
by said hardening or tempering operation.
A plate or projectile made in accordance with my invention is perfectly
homogeneous and hence is preferable to one composed of independent plates of
hard and soft steel or steel and iron rivetted or bolted together.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performned I declare that what I
claim is :-
1. The herein described manufacture of an armour plate or projectile consisting
in first forming the said plate or projectile of iron or low steel, then converting a
portion of the said plate or projectile into steel capable of being tempered, and
finally tempering or hardening this converted portion, substantially as hereinbefore
specified.
2. The herein described manufacture of an armour plate or projectile, consisting
in first forming the projectile of iron or low steel, then converting the inner and
outer faces of the plate or projectile into steel capable of being tempered, and
then tempering or hardening the said surfaces, the temper of the inner surface
being less than that of the outer surface substantially as hereinbefore specified.
3. An armour plate or projectile having a surface of hardened or tempered steel
backed by a cushion of softer iron or steel the whole constituting a single
homogeneous mass substantially as herein before specified.
4. An armour plate or projectile composed of iron or low steel and having its
inner and outer portions of tempered steel, the inner portion of the plate or
projectile having a lower temper than the outer portion substantially, as herein-
before specified.
Dated this 17th day of February 1893.