IMPROVEMENTS IN THE MANUFACTURE OF, HOLLOW SHOT AND SHELLS, AND SIMILAR HOLLOW BODIES, OF CAST IRON OR OTHER CAST METALS
Year: 1855

page_text: LETTERS PATENT to Robert Mallet, Engineer, of Dublin, in Ireland, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF, HOLLOW SHOT
AND SHELLS, AND SIMILAR HOLLOW BODIES, OF CAST IRON OR OTHER CAST
METALS."
Sealed the 6th July 1855, and dated the 26th January 1855.
PROVISIONAL SPECIFICATION left by the said Robert Mallet at the
Office of the Commissioners of Patents, with his Petition, on the 26th
January 1855.
I, ROBERT MALLET, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF HOLLOW SHOT AND SHELLS, AND SIMILAR
HOLLOW BODIES, OF CAST IRON OR OTHER CAST METALS," to be as follows:-
In the ordinary mode of manufacturing hollow shot and shells of cast iron,
cores of loam or sand are employed, which are objectionable for various reasons.
The air or gas which is generated when the melted metal comes in contact
with the core has to escape at the fuse hole or aperture, which, being of small
dimensions, offers a certain resistance to the escape of the air, and thus flaws
and blow-holes are formed in the casting. The core has to be picked out
through the fuse hole or aperture, which is a tedious operation, and portions of
silicious sand or grit frequently remain in the interior of the shell, and may
cause the ignition of the powder in the carriage or firing of the shells.

page_text: By my Invention these defects are avoided. In lieu of employing cores of
loam or sand, which are picked out, as herein-before mentioned, I construct a
thin hollow core or core shell in two or more picces of cast or wrought iron,
and I place this core shell in the mould and pour the melted iron around
it. This core shell is not afterwards removed, but remains as a lining to the
shell. For spherical shells, the core shell is cast in two hemispherical pieces,
one of which fits into a rebate in the other. These hemispheres may be east
in sand or loam or metallic moulds, and are of such forms as to deliver their
own cores, and are thus easily cast. One hemisphere has a boss projecting
outwards, which is tapped to receive the fuse in the ordinary manner. The
other hemisphere has a boss projecting inwards, which is tapped to receive a
hollow tapered core bar, perforated with holes, for the escape of the air or gas.
This core bar is fitted to the boxes or moulds employed for casting the shells,
and serves to support the core shell in its proper place, and is such that any
part of the shell may be cast uppermost in the mould. When the metal bas
been poured into the mould and has become solid, the core bar is unscrewed
and employed repeatedly in a similar manner. Elongated or other shells, or
hollow shot, or similar hollow bodies, are manufactured in a similar manner
by making the core shell of the form required for their interior, and in two or
more pieces, and casting the melted iron around it. The usual lugs, rings, or
ears for lifting the shell may be made of wrought iron, and laid in the mould
before pouring in the melted metal in the usual manner, or by any other
method. The thickness of the core shell may be just sufficient to prevent its
being melted by the hot metal, or it may be of greater thickness, if preferred,
and of equal thickness all over, or thicker in one part than in another. These
shells will produce a greater number of fragments in their explosion than the
ordinary shells. The core shell may be clean on the exterior, or it may be
covered with a thin layer of chalk, or clay-wash, or other suitable coating to
slightly separate it from the rest of the shell; or it may be galvanized or
otherwise coated, to cause more complete union with the cast metal. The
details of the manufacture may be varied, and the core shells may be annealed
or rendered malleable after casting them, and sheet iron core shells struck up
by dies may be employed; but in all cases the core is hollow, and formed of
two or more pieces of metal, and remains as a lining to the finished article.
I have mentioned cast iron as the metal employed, but other metals may be
substituted for it, the core being made of a metal having, the same or a less
degree of fusibility than the metal employed for the shell or outer portion of
the casting.
:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Mallet in the Great Seal Patent Office on the
23rd July 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MALLET, Engineer, of Dublin, in Ireland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of January, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Robert Mallet, Her special licence that I, the said Robert Mallet, my
executors, administrators, and assigns, or such others as I, the said Robert
Mallet, 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 THE MANUFACTURE OF HOLLOW SHOT AND SHELLS, AND SIMILAR HOLLOW BODIES
OF CAST IRON OR OTHER CAST METALS," upon the condition (amongst others)
that I, the said Robert Mallet, 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 Robert Mallet, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment thereof, reference being had to the accompanying Drawings, and to the
figures and letters marked thereon, that is to say:-
In the ordinary mode of manufacturing hollow shot and shells of cast iron,
cores of loam or sand with other substances are employed, which are objection-
able for various reasons. The air or gas which is generated when the melted
metal comes in contact with the core has to escape at the fuse hole or aperture,
which, being of small dimensions, offers a certain resistance to the escape of
the air, and thus flaws and blow-holes are formed in the casting. The core
has to be picked out through the fuse hole or aperture, which is a tedious
operation, and portions of silicious sand or grit frequently remain in the
interior of the shell, and may cause the ignition of the powder in the carriage
for firing of the shells.

page_text: By my Invention these defects are avoided. In lieu of employing cores of
loam or sand, which are picked out, as herein-before mentioned, I construct a
thin hollow core or core shell in two or more pieces of cast or wrought iron,
and I place this core shell in the mould, and pour the melted iron around it.
This core shell is not afterwards removed, but remains as a lining to the shell.
For the ordinary spherical shells or hollow shot, the core shell is: cast in two
hemispherical pieces, one of which fits into a rebate in the other, as shown in
Figure 1, Sheet I., of the accompanying. Drawings, which is a section.of.a
shell manufactured according to my Invention.. A and B are the two
hemispheres forming the core shell; C. is the body of the shell cast upon the
core shell. One of the hemispheres A has a boss, or nipple a projecting out-
wards, and tapped to receive the fuse which is. screwed into, it. The other
hemisphere B has a smaller boss b projecting inwards, and, tapped with a
screw of smaller diameter than that of the other boss a.. The edge of the
hemisphere A enters a rebate in the other hemisphere B.
Figure 2 is a section of the core shell mounted on a wrought-iron, core
bar. D. The core bar is made with a shoulder at c,. and. tapers to the end d,
which is screwed to fit the screw in the boss b.. The part of the core bar
which passes through the fuse hole at a is not screwed into it, but just fits and
touches the tops of, the threads of the screw.. The; core bar has another
shoulder or collar e, which fits in semicircular recesses in the boxes in which
the, shell, is cast. E and F are portions of these boxes. The core bar D is
hollow, and has one or more lateral apertures f, opening into the interior of
the core shell, to allow of the free escape of the air expanded in the interior
of the core by heat in the process of casting... Figure 9, Sheet II., is a vertical
section of a mould box G, H, for casting the core shells, and Figure 10 is a plan
of the lower part G of the same. I prefer to make the mould boxes circular,
and with their edges.turned and fitted, and I ram the sand or loam into them
on a bench or plate with grooves, or rebates, to which the boxes are fitted, and
to which are attached patterns or blocks of forms corresponding, to the interior
and exterior surfaces of the hemisphere. By this means the hemispheres are
accurately moulded with great ease. They may, however, be moulded in the
ordinary or any other manner if desired. g and h are runners. or "gates,".for
the entrance of the metal and the escape of air.. Figure 3, Sheet I.,. shows
one of the hemispheres thus cast. The boss a is afterwards bored out and
tapped, and the outer surface of the boss is faced. The two hemispheres are
fixed on the core bar, as shewn in Figure 2, Sheet I., with a little fine fluid
luting of clay and coal dust blacking in the rebate, and a loose washer of
coarse brown paper or pasteboard is put between the collar c and the boss a.

page_text: "
The core bar is screwed in so as to secure, the hemispheres together, and the
core shell is placed in the mould box, as shewn in Figure 11, Sheet II., which
is a plan, and Figure 12, which is a vertical section of the mould box.
Figures 13 and 14 of the same Sheet are elevations of the same. E is the
bottom part of the mould box, and F is the top part. The mould boxes, are
rammed in the manner herein-before mentioned for moulding the core shells,
or in any other manner,. and they are placed together with the core shell
between them.... The core
shell is secured in its proper,place in the mould box
by the core bar D, and its collar e entering the, recesses in the top and bottom
parts. of the box, i is a runner or "gate" for the entrance of the melted
metal, and, which should be so placed tangentially to the inner or core. shell
that the fluid, metal may, not strike directly upon it, and so endanger the
melting a hole through it., j, is a rising head for the escape of the air. The
melted metal is poured into the mould,, and fills the space C between the core
shell, and, the mould... When the metal has solidified, the shell is removed
from the mould,, and the core bar D is unscrewed and removed; the shell is
then complete, and when cold is ready to receive its charge and fuse... Rings,
cars, or lugs of wrought iron for lifting the shell may be introduced in the
moulds, so as to become fixed in the metal of the shell if required.
:
Figures 15 and 16, Sheet II., are vertical sections of a mould box for
casting shells in a similar manner to that herein-before, described, except, that
the core bar D is placed, in a vertical instead of, a horizontal position. The
vertical position is that best adapted for large shells.
Figure 4, Sheet I., is a section of a shell similar to that shewn in Figure, 1,
but of smaller, dimensions. The core shell may be made very thin, provided
it is sufficiently thick to prevent its being melted by the contact of the melted
metal which is poured around it, or it may be made thicker, so that when the
shell bursts, its fragments may act in a similar manner to those of the shell
itself. It may also be made thicker in one part than in another.
山
Figure 5.is a section of a shell with a thick core shell. The body of the
shell may be made thicker round the junction of the hemispheres of; the core
shell to compensate for the want of strength in the core shell at that part. In
this. Figure, the junction of the hemispheres is shown bevilled or conical, in
lieu of rebated.
Figure 6 is a section of another shell manufactured according to my Inven-
tion. The core shell A, B, is made thicker at intervals by a series of ribs k, k,
which cross each other, so as to divide the surface into a number of parts.or
segments. The body of the shell C is thus rendered thinner and weaker at
the lines-which correspond to the ribs k, and when the shell bursts, it is sepa-

page_text: rated into a greater number of fragments or splinters than if made in the
ordinary manner.
If it be required to prevent the outer portion of the shell from coming into
close contact with the 'core shell, this is effected by covering the core shell
with a more or less thick coating of clay wash, and drying it before casting
the body of the shell upon it. On the other hand, if it be required to effect a
closer union between the core shell and the 'body of the shell, the core shell
may be cleaned or galvanized or otherwise coated, to cause it to unite with the
body of the shell, or fluxes may be employed to cause their union.
Figure 7 is á section, shewing my Invention as adapted to the manufacture
of Captain Boxer's shrapnel shell. The core shell consists of three pieces
I, J, and K, which are fitted together with rebates. The piece J divides the
shell into two unequal chambers, the larger of which is intended to receive
the bullets or other projectiles, while the smaller chamber, between J and K,
receives the charge of powder for bursting the shell. Each of the pieces
J, J, and K has a boss or nipple l, m, n, bored, and tapped with a screw.
Two core bars are employed in casting the shell, as shewn in Figure 8. Lis
a core bar, which is hollow, or perforated from end to end; it passes freely
through the boss l, and is screwed into the boss m, so as to hold the pieces
I and J firmly together. The other core bar M passes freely through the
boss n, and is also screwed into the boss m, which is made sufficiently long to
receive the ends of both core bars. The piece K is thus firmly pressed
against the piece J by the shoulder of the core bar M. The core bar M is
hollow at its end, or throughout, and has one or more lateral openings com-
municating with the small chamber between J and K, while the core bar L
has one or more lateral apertures communicating with the larger chamber
between I and J. The air has thus free egress through the core bars. The
core shell and core bars are placed in the mould box, and the shell cast upon
them, as before. The mould box is made with recesses on the two opposite
sides to receive the two core bars. After the shell has been cast, the core bars
are unscrewed, and a plug is screwed into the boss m, as shewn at p in
Figure 7. The bullets or other missiles are placed in the larger chamber,
and a plug is screwed into the boss l. The gunpowder is placed in the smaller
chamber, and the fuse is screwed into the boss n. The powder is thus
separated from the bullets or other missiles by the partition J.
Shells of other forms, such as egg-shaped or conical shells, or other hollow
bodies of cast metal, may be manufactured in a similar manner by varying
the forms of the moulds and core shells. The core shells' may also be made
of several pieces of metal fitted together, if required. Several of the core
"

page_text: shells or the shells themselves may be moulded and cast at once in the same
box, but I consider it more convenient to cast them in separate boxes, as
herein-before described. The core shells may be made of ordinary cast
iron, as herein-before described, or they may be made of cast iron annealed
or decarbonized, so as to render them tough and less fusible. They may
also be made of wrought iron, stamped or struck up in dies into the
hemispherical or other requisite form.
Hollow bodies of brass or other metals or alloys may be manufactured in a
similar manner, the core being of a metal having the same or a less degree of
fusibility than the metal employed for the outer portion of the casting. When
the core is thin, and of the same or nearly the same degree of fusibility as the
outer portion of the casting, care must be taken that the temperature of
the melted metal be not raised so high above its melting point, or other
conditions produced such as to fuse and destroy the core. The moulds for
casting the cores and those for casting the shells or other hollow bodies may
be of green sand, or of dry sand or loam, or of metal or other suitable
material.
Having now described the nature of my said Invention, and in what
manner the same is to be performed, I wish it to be understood that what I
claim is,-
Firstly, the manufacture of hollow shot and shells and similar hollow bodies
of cast iron or other cast metals, by pouring the melted metal into a mould
containing a hollow metallic core made in two or more pieces, and which core
ultimately remains as a lining to the shell or other hollow body, as herein-
before described.
Secondly, the mode or modes herein-before described of applying the hollow
metallic core made in two or more pieces in combination with the core bar or
bars, in the manufacture of hollow shot and shells and similar hollow bodies
of cast iron or other cast metals.
In witness whereof, I, the said Robert Mallet, have hereunto set my
hand and seal, this Nineteenth day of July, in the year of our Lord
One thousand eight hundred and fifty-five.
ROBERT MALLET. (L.S.)