AN IN- PROVEMENT IN SAWS FOR COTTON GINS
Year: 1866

page_text: LETTERS PATENT to Thomas Cowell Craven, of Albany, in the State of
New York, United States of America, for the Invention of "AN IN-
PROVEMENT IN SAWS FOR COTTON GINS."
Sealed the 21st December 1866, and dated the 2nd July 1866.
PROVISIONAL SPECIFICATION left by the said Thomas Cowell Craven
at the Office of the Commissioners of Patents, with his Petition, on
the 2nd July 1866.
I, THOMAS COWELL CRAVEN, of Albany, in the State of New York, United
States of America, do hereby declaro the nature of the said Invention for
"AN IMPROVEMENT IN SAWS FOR COTTON GINS," to be as follows:-
In cotton gins heretofore constructed the cotton is drawn away from the
seeds by the teeth of a series of saws forming a cylinder, the seeds them-
selves being kept back by guards or strippers; the teeth of these saws
are very liable to cut and injure the cotton and reduce its market value,
besides which the teeth are of such a shape that the cotton seeds are often
broken and pieces of the seeds pass away with the cotton.
The nature of my said Invention consists in an improved saw for the
cylinder of cotton gins, the saw being formed with hook-shaped teeth that are
rounded upon their elges so as not to cut or injure the cotton and not to break
the sceds.
In order to form each saw I take a circular plate of steel with a

page_text: polygonal hole in the centre, and place the same on an arbor that is moved
around progressively by a ratchet, the amount necessary between each stroke
of a punch that is provided to cut out one or more teeth each blow. Each
tooth is to be formed of a hooked shape, the exterior or back of the tooth
being convex and the under side concave; I then subject the saw 'to the
action of dies that are shaped to correspond with the teeth, and round the
angles or edges of the teeth, so that a section through one of the teeth would
be a flattened ellipse; the dies also bring the teeth to a sharp or needle-
shaped point. A ginning cylinder formed of a series of these saws upon an
axis or polygonal shaft, with packing discs intervening, presents a large
number of smooth teeth that draw the cotton away from the seeds without
injury to the cotton and without breaking the seeds.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Cowell-Craven in the Great Seal Patent Office on
the 28th December 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
COWELL CRAVEN, of Albany, in the State of New York, United States of
America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of July, in the year of our Lord One
thousand eight hundred and sixty-six, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Thomas Cowell Craven, Her special license that I, the said Thomas Cowell
Craven, my executors, administrators, and assigns, or such others as I, the said
Thomas Cowell Craven, 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 "AN
IMPROVEMENT IN SAWS FOR COTTON GINS," upon the condition (amongst others)
that the said Thomas Cowell Craven, by an instrument in writing under
my hand and seal, 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.

page_text: NOW KNOW YE, that I, the said Thomas Cowell Craven, 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 Drawing hereunto
annexed, and to the letters and figures marked thereon (that is to say) :-
In cotton gins heretofore constructed the cotton is drawn away from the
seeds by the teeth of a series of saws forming a cylinder, the seeds themselves
being kept back by guards or strippers. The teeth of these saws are very
liable to cut and injure the cotton and reduce its market value, beside which
the teeth are of such a shape that the cotton seeds are often broken and pieces
of the seeds pass away with the cotton.
The nature of my said Invention consists in an improved saw for the
cylinder of cotton gins, said saw being formed with hook-shaped teeth that are
rounded upon their edges so as not to cut or injure the cotton and not to break
the seeds. In order to form each saw I take a circular plate of steel with a
polygonal hole in the center, and place the same on an arbor that is moved
around progressively by a ratchet the amount necessary between each stroke
of a punch that is provided to cut out one or more teeth each blow. Each
tooth is best to be formed of a hook shape, the exterior or back of the tooth
being convex and the under sido concave, the tooth itself forming a point; I
then subject the saw to the action of dies that are shaped to correspond with
the teeth and round the angles or edges of the teeth, so that a section through
one of the teeth would be a flattened ellipse; the dies also bring the teeth to
a sharp or needle-shaped point. A ginning cylinder formed of a series of
these saws upon an axis or polygonal shaft with packing disks intervening
presents a large number of smooth teeth that draw the cotton away from the
seeds without injury to the cotton and without breaking the seeds.
In the Drawing, Fig. 1 represents in about twice the usual dimensions,
several of the teeth upon a portion of the edge of a saw, the teeth at a, a,
being in the form in which they are first cut out, and at b with the edges
rounded and smoothed by the action of the dies; Fig. 2 is a section of the
finished teeth at the line x, x; Fig. 3 is a plan, and Fig. 4 a sectional
elevation of the dies that I employ for rounding the teeth; these dies are
fitted in any desired press so as to be opened and closed with the required
power, and the saw is fed around tooth by tooth to the action of these dies
by suitable mechanism. The dies themselves are formed is three steps or
gradations, each of which contains one or more recesses for the teeth; the step c
of the dies is formed with a cavity in each face, corresponding exactly when the
dies are closed to the finished tooth, so that the teeth of the saw as they come

page_text: (as at a) from the first or cutting operation are compressed, rounded, pointed,
and smoothed, so that there are no sharp angles to injure the staple of the
cotton. At d the step is formed with a cavity entirely on one side and a plain
surface on the opposite die, and at é the reverse step is made, the cavity being
entirely on the other die; these steps may be gradual or sudden. The object
of this construction of die is to clean out between the teeth, first in one
direction and then the other as they are successively presented, and remove
any burs, fins, or roughness that may result from the action of the part c of
the dies, or from cutting out the teeth, and thereby make the teeth entirely
smooth and adapted to the cotton gin, as aforesaid. The edges of the saw
teeth might be rounded by the action of rollers with the shape of the teeth
countersunk, and these rollers should be conical, so as to revolve and press
upon the teeth to round them.
What I claim and desire to secure by Letters Patent is,-
First, a saw for cotton gins formed with rounded teeth of the character
specified by the means, and as and for the purposes set forth.
--Second, I claim-the-dies for rounding the teeth and removing any sharpness
or burs, said dies being formed with the steps or gradations as and for the
purposes set forth.
In witness whereof, I, the said Thomas Cowell Craven, have hereunto
set my band and seal, this Twenty-eighth day of November, in the
year of our Lord One thousand eight hundred and sixty-six.
Witnesses,
CHAS. LI. SMITH,
121, Nassau St.,
New York,
GEO. D. WALKER,
121, Nassau St,
New York.
THOS. C. CRAVEN. (L.S.)