Improvement in the Art of Making Ordnance.
Year: 1890

page_text: Date of Application, 24th Dec., 1890
Complete Specification Left; 19th Sept., 1691-Accepted, 24th Oct:, 1891
PROVISIONAL SPECIFICATION.
Improvement in the Art of Making Ordnance.
I, RICHARD JORDAN GATLING, living at No. 297 Main Street, in Hartford,
Hartford County in the State of Connecticut, United States of America,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an improved method of producing heavy ordnance, the
object being to provide improved means for producing large guns, whereby their
power to resist the effects of long continued firing is greatly increased, and the cost
of producing the same is materially reduced.
Heretofore heavy guns have been cast solid, or made of forged steel, upon, what
is known as the built up principle." Large guns, when cast solid, are left
invariably under tensions from unequal heating and cooling, which tensions often
cause ruptures of such guns in firing.
The object of my invention is to provide a method for casting guns which
obviates all of the abovenamed inconveniences, and, as above referred to, results in
the production of a gun of greatly increased endurance as compared with those
heretofore made.
In other words; in constructing a high power gun, the strain should, if possible
be so distributed that when the powder pressure acts cach portion should offer the
same resistance radially and longitudinally to the strain. These results my system
accomplishes.
I attain these objects by constructing a circular pit in a foundry of such depth.
as the length of the gun to be cast therein requires. The said pit is provided with
a shield or cover of iron and is adapted to be heated to a high temperature,
together with the parts of the gun which are placed therein, preparatory to making
the final casting which completes the founding of the gun, by means of a series of
gas-burners arranged around the interior of the pit-wall, or by other suitable means,
in order to suitably expand the below-described outer shell of the gun.
The entire gun when completed in the pit consists of a central core portion of
cast or wrought steel, or other suitable metal, with a central bore therein, and is
lowered into the pit in a central vertical position therein and there properly
supported, and said core has connected with its lower end suitable water or air
conducting pipes for the purpose of sending a cooling current through it after the
below mentioned casting has taken place. Said core is adapted to be enlarged to
the proper calibre for the finished gun. A cylindrical metallic shell of suitable
cast or wrought metal is then lowered into the pit over said core and there
properly supported in a vertical position with said core extending through its axis.
I then complete the gun-casting by pouring a body of melted metal into the space
between the said shell and the said core, and the parts are thereafter left to cool
gradually in the pit, the exterior portion, or shell, of the gun, by exposure to the
air becoming cooled gradually and rigidly shrunken upon the parts within it.
After the gun-casting so formed shall have become cool it is taken from the pit and
bored and finished in the usual way, and if desired a trunnion-bend may be secured
thereto in the usual manner.
Dated this Sixth day of December 1890.

page_text: COMPLETE SPECIFICATION.
*Improvement in the Art of Making Ordnance.
I, RICHARD JORDAN GATLING of 297 Main Street in Hartford, Hartford
County, and State of Connecticut, United States of America Mechanical Engineer
do hereby declare the nature of this invention,, and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:
*
This invention relates to an improved method of producing heavy ordnance, the
object being to provide improved means for producing large guns, whereby their
power to resist the effects of long continued firing is greatly increased, and the cost
of producing the same is materially reduced.
I attain these objects by the mechanism illustrated in the accompanying drawing,
in which
Figure 1 illustrates in vertical section, a pit which is adapted to be used in the
partial casting of a gun and for carrying out my improved method of constructing
the same, this figure illustrating in longitudinal section in said pit, the parts of a
gun in the positions which they occupy, relatively, after said parts shall have been
united by casting the final portion thereof.
Figure 2 is a plan view of said pit.
Figure 3 is a transverse section of the pit about on line xa, Figure 1.
Figure 4 is a side elevation of the completed gun, partly in longitudinal section.
Heretofore heavy guns have been cast solid, or made of forged steel, upon what
is known as the "built up principle." Large guns, when cast solid, are left
invariably under tensions from unequal heating and cooling, which tensions often
cause, ruptures of such guns in firing. The weakness of "built up" guns grows
out of the fact that they are made out of many pieces, having many transverse
joints, and the metal parts not being homogeneous are often left under unequal
strains, which are detrimental to the lifetime of such guns.
The object of my invention is to provide a method for casting guns which obviates
all of the above-named inconveniences, and, as above referred to, results in the
production of a gun of greatly increased endurance as compared with those
heretofore made. In other words; in constructing a high power gun, the strain
should, if possible be so distributed that when the powder pressure acts each
portion should offer the same resistance radially and longitudinally to the strain.
These results my system, accomplishes.
A, in the drawing, indicates a circular pit of such depth as the length of the gun
to be cast therein requires, having walls of masonry, and preferably, a bottom, B,
of, iron, cast in proper form to receive a centering block, D, also of iron, and having
a recess in its upper side to receive the principal part of a metallic steadying
ring, E, which is made in two equal sections for convenience in placing in the pit.
The pit, A, may be constructed in the earth in or near any suitable foundry, and
in practice a convenient underground passage is made whereby access may be had
to the central portion of the under side of the pit, for the purpose of connecting a
pipe thereto, hereinafter described, and of disconnecting the same therefrom.
Said casting-pit is provided with a shield or cover, h, of iron, made preferably in
half or quarter sections (as indicated in Figure 1) for convenience in placing it in,
and removing it from the pit, and said cover rests on suitable brackets, J, attached
to the inner wall of the pit. Said cover, h, is provided with eye-bolts, 3, to which
hoisting chains may be attached.
The pit, A, is adapted to be heated to a high-temperature preparatory to making
the final casting which completes, the founding of the gun, and to effect said heating
of the pit a series of gas burners, 4, is arranged around the interior of the pit
wall which buruers are suitably connected to gas-conducting pipes, 5, and project
through said wall, as shown.

page_text: The complete gun casting which is shown in section in Figure 1, consists of a
central core portion, 6, which is cast or wrought of suitable metal with a central
bore 7, therein and it is lowered into the pit, its lower end resting upon the
centering block, D, and having such an engagement therewith that it is maintained
in a central position within the walls of the pit. The upper end of the core
portion, 6, of the gun is supported by the braces, 8, and screw operating rings, 9,
whereby the upper end of said core is accurately adjusted to a central position
between the walls of the pit. The said rings, 9, turn freely on the horizontal pro-
jecting studs, 10, which are firmly bolted to the pit walls as shown. Flanges are
formed near the inner extremities of said braces, 8, which bear against the surface
of the core, 6, and said extremities enter recesses in the surface of said core
whereby the braces are prevented from becoming displaced. The said bore, 7, in
the core, 6, is of any convenient size to admit of the passage therethrough of air or
water, as below described, and is adapted to be enlarged by boring, or finished to
the proper calibre for the finished gun. The said complete gun-casting also
consists of a cylindrical metallic shell, K, cast preferably or wrought of suitable
steel which is then lowered into the pit in the position shown in Figure 1, its lower
end resting upon said centering block D, and surrounded and backed up by the
steadying ring, E, and the upper end of said shell, K, is supported within the
walls of the pit by braces, screw-operating rings and studs similar to those
supporting the upper end of the core-piece, 6, and the middle portion of said shell
is supported against lateral deflection by similar devices, as shown.
The said complete gun-casting consists, furthermore, of an intermediate metallic
body, H, preferably of steel which is poured in a molten condition into the space, o,
between the shell, K, and the gun-tube, 6, after the latter shall have been put in
position one within the other, as above described.
After the said tube, 6, or center-piece of the gun shall have been placed in
position in the pit, as above described, a tube, 12, is passed through the bottom B
of the pit and through the centering block, D, and is screwed or otherwise securely
connected into the lower end of the hore 7, of said center-piece, and a nut 13, is
screwed onto the lower end of said tube 12, and against the under side of the pit
bottom, B, said tube with its nut, 13, tending to bind the pit bottom and the
center-piece, 6, more closely one to the other.
For the purpose of providing means for cooling the center-picce, 6, of the gun
from its bore outward, gradually and steadily after the final pouring of the inter-
mediate portion, H, of the gun, whereby cooling fractures in proximity to said bore
are obviated, a pipe, 14, is connected to the lower end of said tube, 12, which is
adapted to conduct cold water or air through said bore for the purpose aforesaid,
and said water or air after passing through said bore escapes therefrom by a
pipe, 15, connected with the upper end of the center-piece, 6, as shown in
Figure 1.
After the aforesaid center-piece, 6, and the said shell K, shall have been secured
in place in the pit, as described, and before the intermediate portion, H, of the gun
shall have been poured therebetween as described, the cover, h, is put in place
within the pit, and the gas burners 4, are lighted thereby heating the interior of
the pit very hot, and finally bringing the said outer shell, K, to, or nearly-to, a red--
hot condition whereby it is sensibly expanded, and also the core-piece, 6, is heated
to a considerable degree, but of course to a lesser degree than the shell K. While
the said shell and core-piece are in said heated condition the molten metal which
is to compose the intermediate portion of the gun H, is poured into the space
between said two parts completely and solidly filling the same with molten metal.
The gun so formed is then allowed to cool, the exterior portion thereof by
exposure to the air and the core portion, 6, by the passage of cold water or air
through the bore, 7, thereof, as aforesaid, and in the process of cooling the exterior
shell, K, becomes rigidly shrunken upon the parts within it.
After the gun-casting so formed shall have become cool the above described
lateral braces are removed and the casting is taken from the pit and bored and

page_text: finished in the usual way, (said tube 12, and the pipes 14 and 15, having been first
removed) and if desired a trunnion band, L, may be secured thereto in the usual
manner as shown in Figure 4. That is, to say, said trunnion-band with the
trunnions thereon is made, preferably by casting the same from steel, then boring
it to the proper internal diameter, or one slightly less than that of the part of
the gun to which it is to be applied, then heating said band to expand it, and
then placing it on the gun. The band then contracts and becomes firmly fixed on
the gun.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim, is:
1. The improved method of making ordnance which consists in first forming a
metallic center-piece for the gun, secondly providing an outer metallic shell
therefor and placing said shell over said center-piece leaving a space between
the latter and said shell and heating the latter to expand it, and finally pouring
molten metal intermediately between said shell and center-piece and permitting
said outer shell to cool and shrink upon, and bind said intermediately placed metal
firmly against said center-piece.
2. The improved method of making ordnance which consists in first forming a
metallic center-piece for the gun, secondly providing an outer metallic shell
therefor and placing said shell over said center-piece leaving a space between the
latter and said shell, and finally pouring molten metal intermediately between said
shell and center-piece.
Dated this Ninth day of September 1891
RICHARD J. GATLING,
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.