IMPROVEMENTS IN CANNON
Year: 1864

page_text: LETTERS PATENT to David Augüste Burr, of Washington City, United
States of America, now of No. 12, Southampton Buildings, Chancery
Lane, in the County of Middlesex, Civil Engineer, for the Invention of
"IMPROVEMENTS IN CANNON."-A communication from abroad by George
Ferriss, of Utica, State of New York, in the United States aforesaid.
Sealed the 29th April 1864, and dated the 19th January 1864.
PROVISIONAL SPECIFICATION left by the said David Auguste Burr
at the Office of the Commissioners of Patents, with his Petition, on the
19th January 1864.
I, DAVID AUGUSTE BURR, of Washington City, United States of America,
now of No. 12, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Civil Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN CANNON," a communication, to be as follows:-
These improvements relate chiefly to a novel method of building up and
forging heavy ordnance, so that there shall be a concentric gradation of
temper and quality of the metal used in a degree more or less uniform from
the centre of the piece outwardly; to a device for securely retaining encircling
bands or rings upon cannon; to the mode of opening and closing the chamber
of a breech-loading cannon; to the manner of securing a perfectly gas-tight
joint in closing this chamber, and to the formation of a longitudinal groove
in, the lower portion of the screw cut in the rearward opening thereof.
In order to obtain a cannon strong enough to withstand the expansive force

page_text: of any charge of powder which can be confined and burnt therein, a series of
metallic disks or cylindrical plates of suitable diameter are welded together
to constitute the body or core of the piece. Each of these disks is formed by
coiling up and welding into a solid piece a bar or "ribbon" made by uniting
together pieces of wrought iron of different qualities, commencing at one end
with the softest, adding others each harder than that preceding it, and ending
with the hardest quality. In coiling up these bars the softest end is placed in
the centre. To complete the gradation of the substance of the gun in quality
and temper radially from its centre, and to obtain the utmost possible strength
in the piece, heavy steel rings may be driven upon the exterior thereof. These
are securely held in place by means of a series of metallic key rings, each
divided at one point, and sprung into rectangular grooves cut in the periphery
of the gun immediately in front of the encasing ring. The key rings are of
such a thickness as to form, when sprung into the grooves, a shoulder or
annular projection, which will prevent the encasing ring from slipping for-
ward. Each succeeding steel ring has a rebate formed upon its inner edge
to pass over the preceding key ring, the last ring being secured by a dowel
pin or other suitable device. The recoil seat or block necessary to close the
loading aperture and chamber of a breech-loading gun is, by this Invention,
secured to the end of an operating screw by means of a mortise and tenon
joint and suitable dowel pin. The recoil seat is made to screw into the rear
opening of the chamber, and the operating screw to which it is attached works
in and is supported by a standard or nut pivoted vertically between arms pro-
jecting rearwardly from the breech of the gun, so that the recoil seat when
withdrawn from the loading aperture may be swung around upon this nut,
affording free access to the chamber.
In order to prevent any portion of the powder with which the
gun may be
loaded from being blown out unburnt by the explosion of the grain first
ignited, a vent tube communicating with an exterior touch-hole is secured to
the centre of the front face of the recoil seat, which tube when the chamber is
closed by this recoil seat will extend to a point at or near its centre. The
charge of powder being ignited through this tube in the centre of its mass,
instead of at the rear end thereof, as has heretofore been customary, will be
wholly consumed and exploded within the gun. The ends of the screw
threads encircling the recoil seat are cut square, and a slot or groove is
channeled out longitudinally in the lower part of the screw aperture in the
breech of the gun, across the threads of the screw, so that any accretions
which may collect or form in its concavities are carried by the ends of the
threads and deposited in this groove. The chamber of the gun is completely

page_text: closed rearwardly, and the joint of its recoil seat therewith rendered perfectly
gas-tight by means of an expansive double-metallic packing flange fitted to the
front or inner face of the recoil seat. This packing flange is composed of a
cylindrical-slitted outer casing, combined with a segmental inner lining, in
such a manner that the joints or slits in the two shall alternate or break onė
upon another. The mouth of the rear opening into the chamber is made
slightly tapering inwardly, so that when the recoil seat is forced therein its
packing flange is compressed and made to fit thereto tightly, and with perfect
accuracy.
By this Invention the stretching power of the substance of the gun, noted
concentrically, and estimated from within outwards, is made to diminish in
proportion to the diminution of the strain thereon. The expansive force
exerted upon the gun in the explosion of a charge of powder therein being
greatest in the centre thereof, the stretching power of its inmost part is made
to exceed the utmost strain which can result from such an explosion therein.
In such a cannon the proportion of powder as compared with the weight of
the projectile to be thrown therefrom, can be so increased that a charge of
powder equal in weight to that of the projectile may be burned in the gun
with perfect safety, and a consequent increase in the initial velocity, range,
and penetrative power of the projectile be obtained.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Augüste Burr in the. Great Seal Patent Office ou
the 24th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
AUGUSTE BURR, of Washington City, United States of America; now of
No. 12, Southampton Buildings, Chancery Lane, in the County of Middlesex,
Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of January in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said David Augüste Burr, Her special license that I, the said David
Auguste Burr, my executors, administrators, and assigns, or such others as I,
the said David Auguste Burr, my executors, administrators; or assigns,
should at any time agree with, and no others, from time to time and all times

page_text: 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 "IMPROVE-
MENTS IN CANNON," a communication, upon the condition (amongst others)
that I, the said David Augüste Burr, my executors or administrators, by an
instrument in writing under my hand and seal, or under the hand and seal of
one of them, 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 David Augüste Burr, 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 statement, reference being had to the accompanying Drawings,
forming a part of this Specification, in which Figure 1 is a side elevation of
the improved breech-loading cannon; Figure 2, an end view of the same,
with the breech screw (E) and its supporting nut (D) removed; Figure 3, a
vertical longitudinal central section of the cannon, with the loading aperture
in its breech closed by the screw-encircled recoil seat (E¹); Figure 4, a top
view thereof as it appears with the breech screw (E) and recoil seat (E¹).
withdrawn from the breech and turned aside to allow the loading of the gun;
Figure 5 represents a portion of the chase of the gun, with some of the
encasing rings removed; Figures 6 and 7 are end views of the recoil seat (E¹),
showing the arrangement of the expanding double flange (N) fitted thereon;
Figures 8 and 9 are views in detail of portions of said expanding flange (N).
Like letters designate corresponding parts in each of the Figures.
This Invention consists, first, of a novel method of building up and forging
heavy ordnance so that there shall be a concentric gradation of temper and
quality of the metal used, in a degree more or less uniform, from the centre of
the piece outwardly.
Second, of a device for securely retaining encircling bands or rings upon
cannon.
Third, of an improved mode of opening and closing the chamber of a
breech-loading cannon.
Fourth, in a peculiar device for securing a perfectly gas-tight joint in closing
this chamber.
And, fifth, in the formation of a longitudinal groove in the lower portion of
the screw, which is cut in the rearward opening thereof.
The main object of the Invention is to increase the velocity and penetrative

page_text: power of projectiles by increasing the mechanical force which impels them
from the gun.
To accomplish this object the cannon illustrated in Figure 1 has been
so constructed as to be capable of containing a charge of powder equal at
least to the weight of the projectile to be fired, and strong enough also to
withstand the expansive force of any charge which can be put therein.
The cannon A, Figure 1, is built up of a central core or body of wrought
iron, encased outwardly in heavy steel bands or rings. In forming the metallic
core B, Figure 3, bars of the proper length are first wrought by welding
together, end to end, pieces of iron of different qualities, commencing with the
softest, adding others, each harder than that preceding, and finally ending with
the hardest quality obtainable. These bars are then coiled up with the
softest end in the centre, and forged into solid disks of the diamater required.
The surface of each disk is afterwards turned or cut down slightly in a lathe
to expose any possible flaw or defect, and a sufficient number of these disks
united into a solid mass by the well-known process of "jump-welding,"
constitute the core of the gun, in the which the chamber is subsequently turned
out. The chase of the gun may be formed in the same manner.
The substitution of bronze or other metallic alloys in the stead of the soft iron
forming the centre of the core, or to precede in the order of gradation from
soft to hard in the quality and temper of the mass is contemplated.
It is evident that this improved mode of obtaining a solid metallic mass, in
which there shall be a gradation of temper and quality in a degree more or
less uniform from its centre outwardly, is not limited in its application to
iron alone, but may be employed in working up any character or description
of metals or metallic compositions which admit of being used in the construction
of cannon.
By this method of forming and forging the core or body proper of the
gun, the stretching power of each layer of its substance is made to diminish
in proportion to its distance from the centre, and consequently from the point
of greatest strain, and provision is thus made for the unequal expansion of the
gun from centre to circumference, the strain and expansion being, as is well
known, always greatest in the centre. The core B should be made of such
dimensions as that the thickness of the metal surrounding the chamber in the
shall be as nearly as possible uniform, and then gradually decrease as it
extends along the chase.
gun
Upon the wrought iron or otherwise metallic body of the gun I drive heavy
steel rings a¹, a², a³, a², a³, aº, a², b₁, b³, b³, b, c, c, Figures 1, 3, and 4. The

page_text: rings a to 7, driven upon the chase of the gun, are securely held in place
against the shoulder formed upon its outer circumference (as illustrated in
Figure 3) by means of a series of iron key rings o, each divided at one point,
and sprung into rectangular grooves so cut in the periphery of the chase so
that the upper edge of each shall coincide with the outer face of the ring to
be held in place, see Figure 3. The iron key rings o, turned to fit accurately
in the grooves, are of a thickness so far exceeding the depth of these grooves
as to form a shoulder. A rebate is cut in the edge of the inner periphery of
the next succeeding steel ring to receive the flange thus formed by the
retaining key ring, as is illustrated in Figures 3 and 5. The last encasing
ring at the muzzle of the gun may be secured by a simple dowel pin m,
Figures 1 and 3. The enlarged portion B of the gun which encloses the
chamber tapers gradually towards the breech, and the steel encasing rings
b¹ to and c¹ and 3 driven thereon, are held in place by the outer ring 6* of the
series, which is screwed thereon, as appears in Figure 3. Upon the ring b²,
which is driven and secured upon the forward part of the enlarged portion of
the gun, I form the trunnions G, G, Figures 1 and 4, for its support, and in
order to make this trunnion ring 61, if possible, more firm and secure, place a
projection or key d, Figure 3, upon the core B of the gun, which fits
into a corresponding recess upon the inner periphery of the trunnion ring
driven thereon.
I do not limit myself in the manufacture of my improved cannon to the use
of any determinate number or exterior form of encasing rings, but their
number and form may be varied as convenience shall suggest, and in fact the
gun constructed of coiled discs as described may be used without encasing
rings, which are added merely out of abundant caution. The superior strength
(as compared with guns of the usual forms and of equal weight) which is
obtained by the novel process of building up and forging this improved cannon,
as has just been described, permits with safety an enlargement of the chamber
therein to an extent heretofore considered altogether unsafe, and thus affords
space for the reception and complete combustion within the gun of a greatly
increased charge of powder in proportion to the weight of the projectile and
as compared with that ordinarily used. The chamber K of the cannon
Figure 3 is made larger in diameter than the bore and extends so far forward
as that, when closed rearwardly by a proper recoil seat or breech block E',
its entire cavity lies in about the centre of the enlarged breech portion of the
The forward end of this enlarged chamber K is made to taper with an
easy ogee curve down to the proper circumference required in the bore of the
gun.

page_text: chase, as illustrated in Figure 3. The rear end or mouth of the chamber is
closed by a recoil seat E' secured to the end of an operating screw E by means
of a mortice and tenon joint f and pin a passing through the same, as appears in
Figure 3. The recoil seat E¹ has also a screw cut upon it and a threaded perfora-
tion is formed to receive it, immediately in the rear of the chamber K, and is
necessarily larger than the bore of the said chamber. The ends of the screw
threads upon the recoil seat are cut square, and a slot n, Figure 2, is channeled
in the lower portion of the screw aperture, longitudinally across its threads,
Figure 3. Hence any dirt or other obstruction which may collect in the grooves of
the screw is carried forward by the ends of the threads until it drops into the re-
ceiving slot n, Figures 2 and 3. An expansive double packing flange, composed
of a slitted outer casing N and a segmental inner casing e, e, e, e, e, e, Figure 7,
is combined with the inner end of the recoil seat E¹ by means of set screws, in
such a manner as that the joints or slits in the two casings shall alternate.
The form of said casings and the manner of combining them with each
other and with the recoil seat E¹ is clearly represented in Figures 3, 4, 6, 7, 8,
and 9 of the accompanying Drawings. It will be observed that the peculiar
arrangement of the segmental portions or staves e of the inner casing is such
that any one of them may be readily withdrawn and replaced without disturbing
the remainder. The expansive packing flange N, thus arranged, forms, in
combination with the end or face of the screw-encircled recoil seat E¹, a closing
piece for the rear open end of the chamber K, which is so turned as to
contract inwardly very gradually to the depth of the flange N, consequently,
as the flange is forced into place to close the chamber, it is compressed and
made to fit with perfect tightness and accuracy therein. The edges of the
segmental portions or staves e forming the inner casing of the packing flango
are so bevelled outwardly as that when forced into the chamber they will cut
away all accretions or fouling upon the sides of the chamber so far as they enter
the same.
It is evident that the expansion of the double packing flange N (made as
described) under the influence of the discharge of the gun, will, in connection
with the clevis, by which it is securely held in place, form a complete gas check.
By withdrawing the dowel pin a, by which the recoil seat E¹ is secured to the
breech screw E, the former may be quickly removed for repair or carried away
to render the gun useless. The operating breech screw E (which I prefer to
make smaller in diameter than the screw-encircled recoil seat E¹) is supported
in a screw aperture formed within a pivoted nut D. This nut is pivoted and
supported between two projecting arms C and C¹, in a vertical plane coincident
with the axis of the gun, (see Figure 2,) and its rotary movement may be

page_text: arrested at pleasure by means of a pin H inserted through an aperture in the
upper arm C. The lower supporting arm C¹ may be formed in one piece
with the gun, (or its outer encasing ring which is screwed thereon,) but the
upper arm C must be made separately and secured to the gun opposite the arm
C after the nut D has been put into its proper position. I therefore secure
this arm C to the gun or to the last encasing ring & thereon by means of a
serrated, bevelled, or dovetailed joint, as shown in Figure 4.
The breech screw E is operated or turned backward and forward by means
of a crank F (Figures 1, 3, and 4), and the pitch of its screw threads is
coincident and uniform with that of the screw threads encircling the recoil
seat E¹. I contemplate the application of my screw-operated and screw-
encircled recoil seat E¹ to all forms and descriptions of breech-loading guns,
however its exterior nut D may be pivoted or supported, for I consider the
use of a recoil seat or breech screw, which screws both through a supporting
nut and into the breech of the gun, as an important and novel improvement in
the mode of closing the chamber of the gun.
The charge of powder in the enlarged chamber K of my improved gun
should be fired in the centre of the mass. To obtain this end I screw a
metallic vent tube W, Figure 3, into the front face of the recoil seat E' in
the centre of its projecting packing flange N; this tube is long enough to
reach the centre of the chamber K, and communicates outwardly by an oblique
aperture i with an opening formed upon the periphery of the recoil seat in
the rear of its screw threads. Into this opening a fulminating friction tubo
or primer is inserted. The vent tube may be quickly unscrewed, removed,
and replaced by a new one when it shall have become imperfect and
unserviceable.
It will be observed that by igniting the powder at or near the centre of its
mass I secure its entire combustion in the gun, and also a more rapid
generation of its full expansive force, burning the largest quantity of powder
in the smallest space of time, and obtaining thereby the advantage and
superiority formed in a short gun over a long one.
In constructing a cannon in which the bore of the chamher shall be much
larger than that of the chase, I prefer to open the same rearwardly in order
to avoid its rapid heating, and to avoid all difficulty in cleaning out the
chamber, and have therefore described particularly a breech-loading gun; yet
it is evident that the improvements in the manufacture of cannon berein set
forth do not all relate exclusively to those which open at the breech, but
have reference to all descriptions of heavy guns:
Having fully described these improvements, and shown how they may be
'

page_text: conveniently carried into effect, I wish it understood that I do not confine
myself to the exact details herein set forth, as these may be modified without
departing from the spirit of the Invention; but I claim,-
First, the manufacture of cannon by the combination of a series of metallic
disks, each of which is formed by coiling up and welding a forged bar or
ribbon of metal whose quality increases in hardness and temper from one end
to the other, the softest end of the bar being placed in the centre of the coil.
Second, the use and arrangement of key rings sprung into grooves formed
upon the periphery of the core of a gun to constitute retaining shoulders for
the purpose of securing outer encircling bands or rings upon the gun, sub-
stantially in the manner herein set forth.
Third, closing the chamber of a gun from the rear by means of a screw-
actuated and screw-encircled recoil seat or breach piece (E¹) when said recoil
seat or breech piece is received into a screw perforation in the breech of the
gun, and combined exteriorly with a supporting nut (D) or its equivalent,
substantially in the manner and for the purpose herein set forth.
Fourth, when the chamber of a gun is rearwardly opened and closed by
means of a screw-actuated recoil seat (E¹) I also claim combining a
tubular-shaped expansible double flange (N) with the inner face of said recoil
seat, substantially in the manner and for the purpose herein set forth.
Fifth, when the chamber of a gun is closed and opened by a screw-encircled
recoil seat or breech-piece (E¹) I also claim forming a longitudinal groove
or slot in the lower part of the screw-cut portion of the opening to said
chamber to serve as a receptacle for the dirt that may accumulate in the
screw threads of the same, substantially in the manner herein set forth.
In witness whereof, I, the said David Augüste Burr, have bereunto set
my
hand and seal, this Second day of May, in the year of our Lord
One thousand eight hundred and sixty-four.
DAVID AUGÜSTE BURR. (L.S.)
Witness,
GEORGE HASELTINE,
International Patent Office,
12, Southampton Buildings,
Chancery Lane,
London, W. C.