Year: 1886

page_text: I ALFRED JULIUS BOULT of 323 High Holborn in the county of Middlesex,
Engineer do hereby declare the nature of this invention (a communication from
abroad by David Mefford Mefford of Toledo in the State of Ohio, United States
of America, Gentleman) and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
The invention has reference to the construction of heavy ordnance, and has as its
object the uniform distribution of strains resulting from the internal pressure and
from the expansion and contraction of the metal.
It consists in the combination of a barrel or gun tube with an external jacket or
reinforce so applied as to leave around the barrel and within the jacket a space
or chamber adapted for the close confinement of air or equivalent fluid.
It also consists in details relating to the manner of applying and securing the
jacket, and to mechanism for automatically relieving the fluid in the act of opening
the breech.
To those familiar with heavy ordnance it is well known that the heat generated
at the time of the discharge causes the inner or central portion of the gun to
expand before the heat is communicated to the exterior and while the outer portion
of the metal remains in its normal condition, and that the gun is thus subjected to
very destructive strains other than those due to the direct pressure of the gas.
It is also known that in guns that are "built up" in sections the strains are
unequally distributed owing to the importance of fitting the parts with the
necessary accuracy. Both of these difficulties are avoided by making use of a
relatively thin gun tube or barrel free to expand and contract independently, in
combination with a strong surrounding reinforce and a fluid body securely confined
between the reinforce and barrel, and surrounding the latter for the double purpose
of lessening the transmission of heat from the inner to the outer part of the gun,
and for transmitting the internal pressure uniformly to the exterior of the gun.
In the accompanying drawings
Figure 1 represents a side elevation of the improved gun.
Figure 2 a longitudinal central section of the same.
Figure 3 is a rear elevation of the breech end of the gun.
Figure 4 is a section through the forward end on a larger scale.
Referring to the drawings:
A represents the barrel or gun tube which may have its bore smooth or rifled as
L
I milnum diameter bath internally and

page_text: externally except that it is provided at the breech with a circumferential flange a.
If desired it may be enlarged internally at the breech to form a powder bed or
chamber of a diameter greater than the bore. B, represents the external jacket or
reinforce of cast iron, steel, wrought metal or other appropriate material, with a
central opening from end to end to admit of the gun tube being extended there-
through. Near its breech end the reinforce is formed with an internally annular
flange b, against the rear face of which the flange a, of the barrel is firmly seated.
In rear of the barrel the opening in the breech of the reinforce is provided with
a screw thread and with a bushing or thimble C, which is secured tightly in place
against the rear face of the flange of the barrel, which is thus forced and held
securely against the flange of the reinforce. The bushing C, is threaded internally
to receive the breech plug D, which may be of any appropriate form. The screw
threads of the two parts may be mutilated or interrupted in the manner commonly
practiced in the construction of breech-loading ordnance, or be otherwise constructed
as preferred. In place of the screw-plug, breeching mechanism of any other
suitable form may be substituted.
At the forward end the reinforce has a conical bush screwed into it with its
opening of flaring or conical form with the larger end toward the muzzle. The
rear or smaller end of the opening has a diameter identical with or but slightly
greater than the external diameter of the barrel.
In order to support the barrel within the front end of the reinforce and produce
between them a close joint, which will admit of their sliding longitudinally with
respect to each other, and compensate for their unequal expansion and contraction,
a ring E is inserted within the flaring mouth of the reinforce, which encircles the
barrel. The interior surface of this ring fits closely upon the barrel while its
exterior surface is tapered to fit snugly within the conical mouth of the reinforce.
The ring is held in place by an internal tube F, shrunk or otherwise secured tightly
on the front of the barrel and bearing at its rear edge against the forward edge of
the ring. For various reasons it is preferred to construct the ring E, and tube F,
in separate pieces but good results may be secured when the rear end of the
tube F, is tapered to fit within the mouth of the reinforce. The tube and the ring
may be of wrought iron, steel or other appropriate material. The barrel will be
commonly constructed of steel or wrought iron, and usually of a thickness much
less than that of the reinforce. Between its points of connection with the barrel
the reinforce has its internal diameter increased in order to produce an annular
fluid chamber e, surrounding the barrel. The provision of this chamber adapted
for the secure confinement of fluid between the reinforce and barrel is the essence
of the invention, and it is to be distinctly understood that the details of the barrel
and reinforce may be modified at will provided this chamber is retained.
It is proposed to provide the reinforce with cocks or valves to permit the
introduction and removal of the fluid and to confine it within the chamber at
the instant of discharging the gun. In order that the gunner may instantly open
the rear cock after the discharge of the gun to permit the expansion of the fluid,
it is proposed to connect one of the cocks with the breech mechanism so that the
two will open and close in unison. Connecting devices of any suitable character
may be employed for this purpose. In the drawing is shown a sliding bar H,
connected to the cock and toothed at its rear end to engage a pinion f, on the
upper end of a vertical shaft g, which latter is connected by nitre-gear with the
pinion crank m, which is used to turn the breech-plug as in other guns at present
known in the art. The upper end of the shaft g, and the sliding rod h, are
sustained by a supporting arm secured to the upper end of the gun. The upper
end of the cock n, is enlarged to form a chamber into which the expanding fluid
may rise, and from which it will automatically return to the gun when the
temperature diminishes. A cock c on the underside of the gun permits the fluid to
be wholly discharged from the chamber if desired.
Water or an aqueous solution of alkali is preferably employed in the gun, but
any other appropriate fluid may be used, the essential requirements being that it

page_text: shall be of such character as to flow readily but at the same time be incompressible
or practically so. Any suitable connections which will permit independent expansion
and contraction of the barrel and reinforce may be employed.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated
to me by my foreign correspondent, I declare that what I claim is :-
1. In a cannon, the combination of a barrel, an encircling reinforce or jacket,
closely joined at its ends to the barrel, and adapted to slide thereon, and a fluid
medium closely confined between the reinforce and barrel and surrounding the
latter substantially as described, whereby the internal strains are transmitted
through the fluid medium to the reinforce.
2. The combination of the thin barrel or gun tube, the relatively thick reinforce
joined at one end rigidly to the barrel, and connected thereto at the opposite end
by a tapered sliding joint, and an incompressible fluid closely confined between the
reinforce and barrel; whereby the internal strains and pressure are transmitted
through the fluid medium to the reinforce, and the barrel permitted to expand and
contract without danger of rupturing the gun.
3. The combination of an internal barrel, and an external reinforce screwed
to the barrel at one end and united thereto at the opposite end by a sliding joint,
said parts constructed to produce a fluid-confining chamber between the barrel and
reinforce as described.
4. The combination of the barrel, the surrounding reinforce connected rigidly to
the barrel at the breech end, and the conical sliding joint connecting said parts at
the forward end, the barrel provided with the internal flange a, in combination
with the reinforce having the internal flange b, the threaded thimble C, and the
breech plug D.
5. In combination with the barrel and the reinforce applied to produce an
intermediate fluid confining chamber, the relief cock having a chamber into which
the expanding fluid may pass and from which it may return automatically to the
chamber.
6. In a gun having a fluid confining chamber as described, a relieving cock
connected with and operating in unison with a breech closing mechanism.
Dated this Oth day of February 1986
ALFRED J. BOULT.