IMPROVE- MENTS IN THE MANUFACTURE OF GUNS to be as follows:
Year: 1885

page_text: I, HIRAM STEVENS MAXIM, of 57º, Hatton Garden, in the County of Middlesex,
Mechanical Engineer do hereby declare the nature of my invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF GUNS to be as follows:―
"
My Invention relates to the manufacture of built-up guns wherein an inner
steel tube or lining is employed.
Heretofore it has been customary to make the steel tubes for guns of this class
from solid cylinders forged in one piece, which requires boring in a machine.
That is to say, the bore has to be entirely formed by cutting out the solid metal,
which is a very tedious and costly operation. One object of my invention is to
so construct such tubes that the work of boring the same will be considerably
simplified and facilitated. For this purpose I employ a series of steel rings or
short tubes, which are united at their ends by brazing to form a tube of the
desired length.
It is well known that, when two pieces of metal are united by brazing, the
strength of the joint will greatly depend upon the extent of area of the brazed
surfaces. In order, therefore, that the tube formed of short tubes or rings, as
above described, shall have great strength at the brazed joints, I make the ends
of the said rings with a series of radial or circumferential grooves and projections,
in such a manner that, when two rings are placed together, the projections in one
ring will fit the grooves in the adjacent ring. I thus provide for an adequate
extent of brazing surfaces.
For brazing the rings together, I prefer to employ a compound of the following
materials in, or about in, the proportions stated, viz:-Seventy parts by weight of
copper, ten parts by weight of silver, and twenty parts by weight of spelter; but
I sometimes use other suitable materials or compounds for this purpose.
The desired number of rings are placed together and secured by a suitable clamp,
they are then heated to a bright red heat and brazed. After brazing, the tube
thus formed is allowed to cool until its temperature is sufficiently lowered; it is
then plunged into oil to toughen it, and is afterwards bored and rifled. But it
is obvious that, as the said tube is made by uniting a series of short hollow
cylinders or rings, this finishing of the bore may be very quickly and inexpensively
effected.

page_text: To increase the strength of the gun as compared with those heretofore manu-
factured, I wind or coil upon the tube formed as above described, a band or ribbon
of finely tempered steel. This band or ribbon is preferably tinned and is coiled or
wound upon the tube in layers, in such a manner that the edges of the coils
of one layer are covered by the central portions of the coils of the adjacent
exterior layer.
Or the said ribbon is wound in any other manner which will ensure the covering
of the edges of the coils of one layer by the coils of the adjacent exterior layer.
This winding on of the steel ribbon is continued until the gun is of the desired
thickness and strength. While winding the outer coils, the ribbon is subjected to
greater tension than while winding the inner coils; when the gun is completed,
therefore, the outer coils are in a high state of tension, whilst the tube is under
great compression and the inner coils are in a low state of tension and are
under compression transversely to the ribbon. The adjacent coils of the ribbon
are sometimes united and the interstices filled up with a metal or alloy, such as
tin or solder, which melts at a lower temperature than that required to affect the
temper of the steel ribbon.
By employing this thin steel ribbon, instead of the thick steel tubes usually
employed for a similar purpose,
I can
use higher grades of steel than those
heretofore used. I am thus enabled to impart very great strength to the gun,
and, at the same time, reduce its weight, as compared with guns heretofore
constructed.
On the exterior of the coiled steel ribbon I place a casing of steel or other
suitable metal. The trunnions are formed integrally with, or firmly secured to,
this casing, and the said casing is made in sections which are firmly united by
.bolts or otherwise.
If this casing is not sufficiently elastic or yielding, strips of india-rubber or other
elastic material are inserted between it and the coiled steel ribbon.

page_text: I, HIRAM STEVENS MAXIM, of 57° Hatton Garden, in the County of Middlesex,
Mechanical Engineer, do hereby declare the nature of my invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF GUNS" and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
My invention relates to the manufacture of built-up guns wherein an inner steel
tube or lining is employed.
Steel tubes for such guns have been heretofore usually manufactured by first
forging solid cylinders and then making the same hollow or tubular by boring
them in a machine; which is a very tedious and costly operation.
One object of my invention is the construction of these tubes in such a manner
that the work of boring the same will be considerably simplified and facilitated.
For this purpose I unite by brazing a sufficient number of steel rings or short
tubular sections to form a hollow cylinder or tube of the desired length and with
a bore so nearly of the required diameter that it can be very easily and cheaply
finished.
Another object of my invention is to make built-up guns of greater strength in
proportion to their weight than those heretofore manufactured. For this purpose
I wind or coil upon an inner tube, formed of rings or tubular sections as above
described, a band or ribbon of finely tempered steel, as hereinafter set forth.
My said invention, moreover, comprises various improvements hereinafter set
forth.
In the accompanying drawing
Figure 1 is a vertical longitudinal central section of a gun manufactured in
accordance with my present invention.
Figure 2 is a longitudinal central section, shewing a portion of one of my guns,
drawn to an enlarged scale.
Figure 3 is an end elevation of one of the aforesaid rings or tubular sections.
Figures 4 and 5 are longitudinal central sections illustrating modifications of my
invention.
Like letters indicate corresponding parts in all the figures.
c is the
a, a indicate the rings or tubular sections, which are united at b to form a long
hollow cylinder which constitutes the inner tube or lining of the gun.
steel band or ribbon which is wound or coiled upon the said inner tube.
It is well known that, when two pieces of metal are united by brazing, the
strength of the joint will greatly depend upon the extent of area of the brazed
surfaces; therefore, to ensure the greatest possible strength at the brazed joints,
I make the ends of the rings a in such a manner as to provide a large surface-
area for brazing. For this purpose the rings a are, in some cases, provided at their
ends with annular grooves and projections, as clearly shewn at 6, in Figures 2
and 3, so that, when the said rings are properly placed together, the projections of
one ring will fit the grooves in the adjacent ring, as shewn in Figure 2.
In some
instances, the grooves and projections are radial instead of annular.

page_text: In some cases I make the hollow cylinders or tubes by brazing together a
sufficient number of conical rings, which are conveniently made of sheet metal
stamped to the required shape, and which fit one within another as shown in
Figure 4.
Or I make the said hollow cylinders or tubes by brazing together a
sufficient number of rings V-shaped in transverse section, which are conveniently
made of sheet metal stamped to the required shape, and which fit one within
another as shown in Figure 5.
It is obvious that the hollow cylinders or tubes made up of rings as above
described can be used either as the inner tubes or linings of built-up guns, or as
the outer portions of such guns.
For brazing together the said rings or tubular sections, I prefer to employ an
alloy or compound of the following materials in, or about in, the proportions
stated, viz-seventy parts by weight of copper, ten parts by weight of silver, and
twenty parts by weight of spelter; but I sometimes use other suitable materials or
alloys for this purpose.
In manufacturing one of my hollow cylinders or tubes, the desired number of
the rings a are placed together and secured by a suitable clamp, the brazing
surfaces having been previously coated or covered with the said material or alloy.
The said rings a are then heated to a bright red heat and brazed.
After brazing,
the hollow cylinder or tube thus formed is allowed to cool until its temperature is
sufficiently lowered; it is then plunged into oil to toughen it, and is afterwards
finished by boring and rifling if necessary. It is obvious that, as the rings a of
which the said tube is constructed have an internal diameter nearly the same as
the required bore of the gun, this finishing may be very quickly and inexpensively
effected.
By the peculiar formation of the brazed surfaces as above described, I provide
for making the tubes as strong, if not stronger, at the brazed joints than at any
other part thereof.
The steel band or ribbon c is coiled or wound.upon the inner tube in layers in
such a manner that the edges of the coils of the successive layers do not coincide
with each other; that is to say, the contiguous edges of the coils of one layer
coincide with, and are covered by, the central portions of the coils of the adjacent
exterior layer. Or the said ribbon is otherwise so wound as to ensure the
covering of the edges of the coils of one layer by the coils of the adjacent exterior
layer. This winding on of the steel ribbon is continued until the gun is of the
desired thickness and strength.
While winding the outer coils, the said ribbon is, as usual, subjected to greater
tension than while winding the inner coils.
The coils of the ribbon are sometimes united and the interstices filled up by
means of a metal or alloy, such as tin or solder, which melts at a lower temperature
than that required to affect the temper of the steel ribbon. In this case, the
ribbon is preferably tinned previous to its being wound or coiled upon the inner
tube, and the soldering is effected either while the ribbon is being wound upon the
tube, or after it has been wound thereon.
By employing this thin steel ribbon instead of the thick steel tubes usually
employed for a similar purpose, I can use higher grades of steel than those
heretofore used. I am thus enabled to impart very great strength to the gun,
and to reduce its weight as compared with guns of the same strength heretofore
constructed.
On the exterior of the coiled steel ribbon, I sometimes fit a casing d of steel or
other suitable metal, to more effectually ensure the retention of the said ribbon in
place and to enable a more highly finished appearance to be imparted to the gun
than would otherwise be practicable. The trunnions are formed integrally with,
or firmly secured to, this casing, and the said casing is made in sections which are
firmly united by bolts e or otherwise.
I sometimes insert strips of india-rubber or other elastic material between the
said casing and the coiled steel ribbon.

page_text: The breech-mechanism shewn in the drawing forms no part of my present
invention and may be replaced by any other suitable mechanism.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
First. The manufacture of hollow cylinders or tubes for the purposes above
specified by brazing together a series of rings or annular pieces or short tubular
sections, substantially as set forth.
Second. The provision of grooves and projections at the ends of the said rings
or tubular sections, substantially as set forth, and for the purpose specified.
Third. A gun having an inner metal tube formed of rings or tubular sections as
above described and a metal band or ribbon wound or coiled thereon, (with or
without the external casing), all substantially as, and for the purposes, set forth.
Fourth. The modification of my invention wherein I employ conical rings in the
manufacture of the hollow cylinders or tubes, substantially as described with
reference to Figure 4 of the drawing.
Fifth. The modification of my invention wherein I employ metal rings V-shaped
in transverse section in the manufacture of the hollow cylinders or tubes, sub-
stantially as described with reference to Figure 5 of the drawing.
Dated this 7th day of October 1885