IMPROVEMENTS IN THE CONSTRUCTION OF PROJECTILES FOR RIFLED CANNON OR ORDNANCE
Year: 1868

page_text: COMPLETE SPECIFICATION filed by the said Edward Augustus Dana
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 5th June 1868, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
AUGUSTUS DANA, of Brookline, in the County of Norfolk, in the State of
Massachusetts, United States of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN THE CONSTRUCTION OF PROJECTILES FOR RIFLED CANNON OR ORDNANCE," and have
petitioned Her Majesty to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said Edward Augustus Dana, do
hereby declare that the following Complete Specification, under my
hand and seal, fully describes and ascertains the nature of the said
Invention, and in what manner the same is to be performed, in and
by the following statement, reference being had to the accompanying
Drawings, of which Fig. 1 is an elevation of the body of the projectile
showing the sabot in section; Fig. 2 is a plan showing the appearance
of the rear end of the projectile; Fig. 3 is a perspective view of the
rear end of the projectile; Fig. 4 is a perspective view of the sabot.

page_text: My present Invention relates to an improvement on the projectile
described in the Specification of the Letters Patent granted to me,
bearing date December 19th, 1865, and numbered 3278.
The object of my present Invention is to secure a sufficient enlarge-
ment of the sabot by the pressure exerted by a comparatively small
expenditure of power, also to avoid excessive pressure laterally against
the walls of the gun.
From examination of the Specification above referred to it will be seen
that my present projectile is similar to the one therein described in
respect to the annular groove B, which serves to receive the surplus
metal of the sabot, and to so fasten the sabot to the body of the pro-
jectile as to prevent it from becoming detached during flight; also in
the arrangement of the ribs k, k, projecting from the inner surface of the
sabot, and arranged to fit the groove e, e, of the body of the projectile,
the objects of which are to prevent the sabot from being rotated on the
conical part C without imparting a corresponding motion to the body of
the projectile, also in the conic frustum or sabot expander C of the body
and the cylindrical tail piece D, a complete description of the con-
struction and function of which will be found in the Specification above
referred to.
My present Invention consists in forming numerous longitudinal
channels c, c, c, c, in said conical portion, so that when the sabot is
in position ready for firing the interior wall of its band shall bear
only upon the ribs between the said channels. When the band is
driven forward by tlie explosion the parts of it which are opposite the
grooves of the gun will be pressed outwardly with them, and the parts
which are opposite the lands of the gun will by reaction be pressed
inwardly into the channels of the body of the projectile, thus securing
a more uniform forward movement of the entire band and relieving
the wedging strain on the gun. Although this improvement is designed
more especially for guns rifled with few grooves, consequently having
broad lands, it works equally well with guns having numerous grooves
and narrow lands. The first effort of the expanding band is outwardly
into the grooves of the gun, but the effort of reaction is caused by the
lands of the gun and also the grooves when filled to compress the soft
metal inwardly into the longitudinal channels made in the conical por-
tion of the projectile.

page_text: Mechanically my projectile is made as follows:-The main body of
the projectile being of such shape and size as may be desired. By
examination of the Drawings it will be seen that the rearward end of my
projectile is formed by the combination of three members namely; first,
an annular groove B, Figures 1 and 3; second, a short truncated cone C,
Figures 1 and 3, having its larger base towards the front of the
projectile; third, a short cylinder D, Figures 1 and 3, being less in
diameter than the smaller base of the truncated cone C. e, Figures 1
and 3, and e, e, e, e, Figure 2, represent longitudinal grooves in the
surface of the truncated cone C, and partly into the annular groove B;
these grooves are made to receive corresponding ribs k, k, k, Figure 4,
formed on the interior of the sabot; these ribs not fitting tightly, but
just so that they may prevent the sabot from revolving independently of
the projectile. The sabot, Figure 4, is made in one piece, being com-
posed of the perforated disk H, H, the ring or band E, and the ribs k, k, k,
on the inside of the ring. The truncated cone C which serves to expand
the sabot and thus fill the grooves of the gun is channelled by a series
of grooves c, c, c, c, Figs. 1, 2, and 3, into which the surplus metal of
the sabot is forced.
Having thus described my said Invention I will now state what I
consider as new and of my Invention.
I claim making the channels or serrations c, c, c, c, in the sabot
expander C when the parts holding working relations thereto are made,
substantially as described and for the purpose set forth.
In witness, whereof, I, the said Edward Augustus Dana, have herc-
unto set my hand and seal, this Eighteenth day of May, A.D.
1868.
EDWARD AUGUSTUS DANA. (L.S.)