IMPROVEMENTS IN CONSTRUCTING HOOPS TO BE USED IN THE MANUFACTURE OF CANNON AND OTHER SIMILAR TUBULAR OR CYLINDRICAL STRUCTURES
Year: 1864

page_text: LETTERS PATENT to Daniel Treadwell, of the City of Cambridge, in the
County of Middlesex, and State of Massachusetts, one of the United.
States of America, for the Invention of "IMPROVEMENTS IN CONSTRUCTING
HOOPS TO BE USED IN THE MANUFACTURE OF CANNON AND OTHER SIMILAR
TUBULAR OR CYLINDRICAL STRUCTURES."
Sealed the 23rd September 1864, and dated the 30th March 1864.
PROVISIONAL SPECIFICATION left by the said Daniel Treadwell at the
Office of the Commissioners of Patents, with his Petition, on the 30th
March 1864.
I, DANIEL TREADWELL, of the City of Cambridge, in the County of Mid-
dlesex, and State of Massachusetts, one of the United States of America, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
CONSTRUCTING HOOPS TO BE USED IN THE MANUFACTURE OF CANNON AND OTHER
SIMILAR TUBULAR OR CYLINDRICAL STRUCTURES," to be as follows:-
By a series of experiments I have demonstrated and determined with some
degree of precision certain facts, a knowledge of which and a practice in
construction in harmony with said facts, are highly useful in the production of
hooped cannon, and other similar structures designed to resist internal strain.
In order that hoops may be produced which shall at all times exert a constant
compression while having a high and permanent degree of elasticity, without
liability to permanent enlargement, under all conditions to which cannon are
subjected in use as ordnance.
The facts which I have developed, and to which I refer are, first, that when

page_text: iron is placed in or about in the condition in which wire comes from the draw
plate, the amount of its permanent extension is far smaller than its elasticity
up to near the breaking point, and that permanent elongation does not
commence until about one half of the breaking strain is applied. Second,
that the amount of the elasticity of such material is increased by its permanent
elongation up to near its breaking point. Third, that when such material has
been subjected to nearly a breaking tension-the- repeated application of a less
degree of tension produces no further permanent extension. Fourth, that
application of less heat than is required to anneal the material (say, about
800° Fah. or less) does not impair its elasticity.. Fifth, that when such
material has been subjected to an annealing heat, and is not again placed in a
condition similar to that in which wire comes from the draw plate, the per-
manent elongation commences at a comparatively low tension, which elongation
is very great as compared with the elasticity of the material so conditioned.
The conclusions I draw from my said experiments are, that when iron hoops
are placed upon a gun in the condition in which they have heretofore been so
placed, viz., soft as they come from the fire after welding and forging heats,
they are not fit for the use to which they are put, as by the act, of firing the
gun on which they are placed they become permanently extended, and no
longer contribute strength to the structures.
My Invention consists in bringing metallic hoops for cannon and other
similar structures, previous to their being put to use, into the condition as
near as may be of wire as it comes from the draw plate by means of cold
hammering, or rolling and stretching when cold, or either of 'said last-named
processes, and in not afterward heating such hoops to a temperature sufficient
to anneal them, a temperature of 800° Fah., or less. being sufficient.to expand
them, so as to cause them to clasp and compress, the cannon, and, being below
the temperature required for annealing:
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Daniel Treadwell in the Great Seal Patent Office on the s
29th September 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DANIEL
TREADWELL, of the City of Cambridge, in the County of Middlesex, and State
of Massachusetts, one of the United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 8
Patent, bearing date the Thirtieth day of March, in the year of our Lord

page_text: 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 Daniel Treadwell, Her special licence that I, the said Daniel Treadwell,
my executors, administrators, and assigns, or such others as I, the said Daniel
Treadwell, 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 CON-
STRUCTING HOOPS TO BE USED IN THE MANUFACTURE OF CANNON AND OTHER SIMILAR
TUBULAR OR CYLINDRICAL STRUCTURES," upon the condition (amongst others)
that I, the said Daniel Treadwell, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
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 Daniel Treadwell, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
My Invention is an improvement in the method of making and applying
the hoops employed in the construction of hooped cannon, by means of which
the hoops are more perfectly adapted to their purposes than when constructed
in the manner heretofore practiced.
The Invention herein described is illustrated by the Drawings which
accompany and form part of this Specification.
On Sheet 1 of the Drawings, the Diagrams 1, 2, 3, and 4, represent
graphically the results of four sets of experiments upon iron wires subjected to
tension, which experiments will be hereafter explained.
Figures 1 and 2, Sheet 2, represent two views of an apparatus designed to
be used in connection with a steam hammer, for condensing and hardening
the hoops; Figures 3 and 4 represent the manner of arranging rolls in a
rolling mill to accomplish the same purpose; and Figures 5 and 6 represent
an apparatus for distending the hoops by internal pressure. In the different
Figures similar letters refer to similar parts.
The principles involved in my method of making and applying the hoops
will be more readily understood from a brief description of four sets of
experiments that I have tried among many others, the results of which are

page_text: represented in the accompanying Diagrams, and show readily to the eye the
action of wrought iron under the several conditions noted, and which have an
important bearing upon the question of how to construct and apply the hoops
for hooped cannon in the best manner. In my experiments I operated upon
pieces of iron wire 140 inches long, and about one-tenth of an inch in diameter,
some of them were in the condition in which they left the drawing dies, others
were annealed, and others had been subjected to temperatures less than are
required for annealing. The wire experimented upon was secured in a frame
and subjected to various tensions of a determined amount, increasing by
degrees until the wire was broken. The smallest force (40 lbs.) was first
applied, and the extent of the elongation of the wire was carefully marked
upon a scale; the tension was then released to see if the elasticity was
sufficient to restore the wire to its former length; then an increased
tension of 80 pounds was applied, and the elongation marked, and the weight
then removed as before, and so on. The result of this series of experiments is
delineated in Diagram 1, and shows that with a tensile strain of 240 pounds the
wire was elongated the amount shown at a, and when the weight was removed
the elasticity of the material was sufficient to restore it to its original length;
but with a greater tension of 280 pounds a small permanent elongation of the
wire was produced of an amount shown by the first line near the zero line in
that column. The results with the succeeding weights that were applied up
to 440 pounds are graphically represented, and show the amount of elasticity
and of permanent elongation in each experiment. The same wire was then
taken for a second series of experiments, and the length after the last
experiment, as indicated at b, Diagram 1, was taken as the zero of the scale of
Diagram 2; the weights were applied as before, and the results are noted
upon the scale; the same wire was then taken for a third series of experi-
ments, and the length left by the preceding experiment at c was taken for the
zero of this; the wire was then heated sufficiently to cause oil to blaze upon
it throughout its entire length, and then subjected to successive weights as
before, till it broke. The result is graphically represented in Diagram 3.
In Diagram 4 is represented the results of a series of experiments with a
wire of the same size and length as in previous experiments after it had been
annealed by simply heating it to a full red heat. The weights noted were
then successively applied and removed as before, and the results recorded, as
is shown in Diagram 4, which shows the permanent elongation and elasticity
exhibited by each experiment in a very striking manner. Other facts having
an immediate connection with these experiments are noted upon Sheet 1, and
sufficiently explain themselves.

page_text: These experiments demonstrate and show with precision several notable
physical facts, all of which are of high importance in the construction of
hooped cannon, in which the hoops are put upon the body of the gun with a
great permanent tension, by expanding them by heat, and placing them upon
the gun, when by cooling they compress the part enclosed.
These facts are, first, that with a piece of iron hardened by compression and
tension in the condition of the hard wire the amount of permanent extension
is far smaller than the elasticity up to near the breaking point, and also that
the permanent elongation does not commence until about one-half of the
breaking strain is applied, a greater tension than would be applied in ordinary
practice.
Second, that the amount or extent of the elasticity is increased by the
permanent elongation of the rod by tension up to near the breaking point.
Third, that when the material has been subjected to a tension of a given
amount (say, 480 pounds, as in Diagram 2), the repeated application
of a tension within that amount produces no further permanent elongation.
Fourth, that the subjecting of the same material to a heat sufficient
to burn oil (supposed to be about 800° Fahrenheit) will not impair its
elasticity.
Fifth, that with the iron annealed, the permanent elongation commences at
a comparatively low tension, far below what it would be subjected to in a gun,
and that its extent is very large in proportion to its elasticity, which shows
how inappropriate to its use upon a cast-iron body is the condition of a hoop.
placed upon a gun if it has been heated to an annealing temperature, and also
that a hoop thus put on would probably be loosened by the discharges of the
gun before the cast-iron body reached its fracturing point.
Now a temperature below that of burning oil will expand the hoops
sufficiently to enable them to be placed upon the gun, although made 1000
less in diameter than the body it is intended to enclose, and by cooling to
compress the body, and produce that condition of permanent tension of the
hoops of the gun that is designed to be produced by the mode of constructing.
guns which is now well known in the arts as the hooped system. My
improved method of constructing the hoops for hooped cannon is founded upon.
these facts, and when carried out substantially as herein-after described; will.
impart to the hoops those qualities which the foregoing experiments show to
be indispensable in the construction of such cannons to enable the material to
produce the best results. I make the hoops of coiled bars or concentric rings
welded up and formed or shaped, but of considerably less internal diameter.
than the boop is to have after it has been hardened and stretched as herein-.

page_text: after directed. I prefer to form the hoop from a broad flat bar coiled spirally
as a ribbon is wound upon its block. After the bar has been coiled or wound
and welded up, and forged into the hoop of proper shape or form by any
suitable means, I place it when cold or at a temperature decidedly below
the annealing point, upon a mandril or cylinder A, Figures 1 and 2, and
placing them upon a suitable anvil block B under a heavy steam hammer C.
I hammer it, stretching or drawing it until the iron becomes hard and con-
densed, and in a condition similar to the hard wire; or the same effect may
be produced by rolling the hoop between a pair of rollers E and F, arranged
äs is shown in Figures 3 and 4, or by any other mechanism that will produce
the result. I then place within the hoop the segmental swages or blocks D,
Figures 5 and 6, to the centre of which is fitted the conical plug G. In this
condition they are placed under a steam hammer and upon an annular anvil
block as is shown, and the plug G is driven in until the internal diameter of
the hoop is enlarged, say, Tou part of its former diameter, or if the iron be of
a soft and tough quality it may be enlarged 2 of its diameter. Instead of
commencing this last operation with the hoop entirely cold it may be heated
to 600° Fahrenheit, and continued slowly as the hoop cools, thus producing
the effect of increasing the hardness and elasticity of the iron. After this
operation the hoop is finished by the lathe to the exact size required to give
tho appropriate compression to the body of the gun and tension to the hoops,
which if the imperfections of workmanship are small, should be from To² to
To of the measured diameter less than the part that it encloses. The hoop
is then heated in an oven or muffle, or by any other suitable means, to a
temperature not up to the annealing point and put in its place upon the gun
and allowed to cool.
From the result of the experiments herein-before described it will be seen
that the hoops thus prepared will have a high degree of elasticity with tho
ability to resist permanent extension from any force to which they are intended
to be subjected in use. These qualities are of the highest importance,
especially when the hoops are placed upon a cast-iron body which has very
little extensibility, as is usually done in the manufacture of hooped cannon,
for without these properties (as is the case when annealed hoops are used),
the hoops may become stretched and loosened by the act of firing, and
thus fail to impart that strength to the gun that they are designed to
contribute:
I do not intend to limit my Invention to the preparing of the hoops by
means of the mechanism mentioned, or by any particular machanism, the
sketches of machinery shown in the Drawings being designed only to illustrate

page_text: the nature of the modifications that may be made in machines in common use
to adapt them to the purpose; nor do I intend to confine my method to
wrought iron alone, as the same operations will apply to steel or other metals,
varying the operations in each case to conform to the inherent properties of
the metal, according to the principles herein-before set forth.
I claim the method herein described of preparing hoops for hooped cannon
or other similar purposes by condensing and hardening the material thereof
when below an annealing temperature by means of compression or extension,
or both, substantially as described, and also in connection therewith, in
heating the same to a degree less than the annealing point for the purpose of
placing them upon the gun, substantially as described.
In witness whereof, I, the said Daniel Treadwell, have hereunto set my
hand and seal, this Sixth day of August, A.D. Eighteen hundred
and sixty-four.
DANIEL TREADWELL. (L.S.).