AN IMPROVED PROJECTILE FOR RIFLED CANNON OR ORDNANCE
Year: 1865

page_text: LETTERS PATENT to Edward Augustus Dana, of Brookline, of the State'
of Massachusetts, of the United States of America, for the Invention of*
"AN IMPROVED PROJECTILE FOR RIFLED CANNON OR ORDNANCE."
Sealed the 13th April 1866, and. dated the 19th December 1865.
COMPLETE SPECIFICATION filed by the said Edward Augustus Dana at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 19th December 1865, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, BE IT'
KNOWN that I, EDWARD AUGUSTUS DANA, of Brookline, of the State of
Massachusetts, of the United States of America, have invented "AN IMPROVED
PROJECTILE FOR RIFLED CANNON OR ORDNANCE," and do hereby declare the
nature of the said Invention, and the manner in which it is to be per-
formed, to be fully described in the following Specification, and represented
in the accompanying Drawings, of which Figure 1 is a side view, and
Figure 2 a longitudinal and axial section of one of the said projectiles;
Figure 8 is a front view of its sabot; Figure 4, a side view of the projectile
without the sabot.
In constructing a rifle projectile which is intended to take the grooves of
the piece from which it is to be fired by the radial enlargement of a soft
metal band or packing placed around the main body of the projectile at 9
near its exterior surface, such enlargement to be effected by the force of the

page_text: powder explosion in the gun-acting directly upon the band or packing afore-
said, the conditions indispensable to its highest efficiency_are, (first), that the
movement by which the band or packing is to be expanded into the grooves
of the gun should be certain, easy, and sufficient; (second), that the move-
ment aforesaid should be so limited as not to produce any undue friction and
strain upon the walls of the piece; (third), that the band or packing and the
main body of the projectile should be so constructed and combined as to
prevent their becoming separated in their flight from the gun when fired, all
of which conditions are fully met in the Invention herein-after described.
The nature of my Invention consists in a peculiar construction of the
body of the projectile and its sabot, the same being substantially as herein-
after set forth.
In the accompanying Drawings, A denotes the main body of the projectile,
which may be chambered for the reception of an explosive charge of powder,
and be of a cylindrical, conoidal, or other suitable form, except in that part
on which the sabot is placed, and with which it is to operate, which is, to be
made as herein-after more particularly explained. At the rear part of the
cylindrical portion of the said body is a groove B, which encompasses the
body, and has a triangular transverse section, it being arranged in the said
body in manner as represented, and in advance of the larger base of the conic
frustum or sabot expander C formed on the body. The lesser base of the
said frustum constitutes a shoulder from which there extends a short cylinder
or prismatic projection D. A series of grooves or channels e, e, cross the said
groove B and conic frustum C, and are to be either cut or cast in the pro-
jectile, and are intended to receive corresponding ribs l, l, formed within and
making part of the sabot E. The said sabot, which may be of brass, pewter,
or other suitable metal, material, or composition having the requisite qualities
of tenacity and softness, is formed as a hollow cylindrical cup with a perfo-
ration or circular hole h through its bottom, such hole being large enough to
receive and fit to the cylindrical projection D of the body of the projectile.
The sabot is thus composed of a bottom piece or flat annulus i and a hollow
cylinder or short tube k, the latter being made with a bore which is frusto-
conical in its front part to encompass the expansive part C of the projectile
body, and when driven thereon to be expanded by it in a manner to cause an
expansion of the tube or part k.
The rear face of the sabot may be either flat or be formed concave in such
manner as to constitute a cup or annular groove, whose edges may be
expanded or forced radially outward by the explosion of the charge of the
cannon when the projectile may be in the act of being driven by such charge

page_text: through the bore of such cannon. Besides being so made, the sabot is to
have a series of ribs 1, 1, projecting from the inner face of its tube i, and
arranged so as to enter the grooves e, e, of the projectile body.
In applying the sabot to the rear part of the body of the projectile, the
part i is to be driven on the part C until the cylinder D may project through
the sabot, or the rear faces of the two be in one plane. When a cannon
loaded with a projectile so made is fired, the force of the explosion of the
charge of gunpowder of such cannon drives the sabot forward on the portion C
until estopped by the shoulder or lesser base thereof. In the meantime the
cylindrical part i of the sabot will be expanded by the portion C, and forced
into the rifled grooves of the gun or cannon, and will finally be more or less
bent down and into the groove B, which will thus be made or caused to serve
in so fastening the sabot to the body of the projectile as to prevent such sabot
from becoming detached therefrom during the flight of the projectile. It is
very important to preserve the sabot in place on the projectile during its flight,
in order to prevent irregularities in its course as well as accidents to friendly
troops, over the heads of which the projectile. may be in flight. The
grooves e, e, and the ribs 1, 2, which enter them, operate to prevent the sabot
from being rotated on the conical part C without imparting a corresponding
motion to the body of the projectile.
One of the chief and distinguishing advantages of my Invention is, that it
enables the manufacturer of the projectile, by regulating the pitch of the
conical portion or surface C and the distance between the interior face of the
disc of the sabot and the shoulder of the shot, to so graduate the expansion of
the packing or sabot as to accommodate it to guns of different forms of rifling,
and also prevent any undue enlargement of the packing or sabot, and con-
sequent unnecessary strain upon the walls of the gun.
I am aware that before my Invention projectiles have been made with
bands or sabots of soft metal or other material, and with conical or tapering
surfaces to receive such sabots, and to expand them into the grooves of a gun
during the discharge of such projectiles through the bore of such gun, there-
fore I do not claim this principle of construction in the abstract.
What I do claim is the combination as well as the arrangement of the
projection D and the frustum C applied to the body of the projectile, and to
-receive and operate with the sabot E, as specified.
I also claim the combination as well as the arrangement of the groove B
with the frustum C and the projection D, as described.
I also claim the sabot made as a cylindrical cup with an opening in its
bottom, substantially as described.

page_text: I also claim the projectile as made with the sabot expander C and the
projection D, and with the sabot to fit the same, with a chamber or space
between the rear end of the expander and the base or bottom of the inner.
part of the sabot.
In witness whereof, I have hereunto set my hand and seal, this 24th day 5
of: November 1865.