Improvements in Explosive Shells or Projectiles.
Year: 1896

page_text: Date of Application, 13th Oct., 1896-Accepted, 14th Nov., 1896
COMPLETE SPECIFICATION.
Improvements in Explosive Shells or Projectiles.
I, LOUIS GATHMANN, of No. 44 Lincoln Avenue, Chicago, Illinois, United
States of America, Mechanical Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The object of my invention is to enable the throwing of an explosive projectile
having a-minimum weight of shell and a large quantity of explosive material from
any approved type of rifled gun without danger of premature explosion and with a
relatively high muzzle velocity.
To attain these objects I provide a projectile having a shell with an open or
partially open base and fill the interior of the shell with explosive material, the
body of the shell being of less diameter than the bore of the gun from which said
projectile is to be fired, so that the expelling gases may enter the base of the
shell and also envelope it. At the front or head end portion of projectile, which
portion is made heavy or massive, I provide guide bands, and between these bands
I fit the usual type of compression band, this compression band taking the rifling
in the gun, and thereby giving the projectile an axial spinning motion in the usual
manner. To guide the projectile and insure perfect envelopment of the main body
thereof by the propelling gases, guiding lugs are provided on the body of the
shell in the rear of said guide and compression bands. The number and position
of these lugs may of course be varied. I also provide a suitable detonating
cartridge conveniently located within the forward end portion of the projectile.
The projectile being open at its base, the main body portion of its shell may be
made very thin, as the pressure of the expelling gases on its exterior portion is
counterbalanced by the interior pressure, but the detonator case and the head
portion of the shell, that part on which there is not any external pressure, must
necessarily be made of sufficient strength to withstand the full pressure of the
powder charge.
In the accompanying drawing, I have shown my invention, the main features of
which I have previously outlined.
Figure 1 is a longitudinal section of a gun showing a shell chamber of unusual
length, the projectile being shown therein in elevation and the powder charge
indicated.
Figures 2, 3 and 4 are enlarged transverse sectional views of the gun and
projectile on corresponding lines of Figure 1.
Figure 5 is a longitudinal sectional view of the projectile on a larger scale.
The shell or projectile of my invention is designed to be used with a gun having
a powder and shell chamber of slightly greater diameter than the rifled bore of the
gun, and I have shown a gun thus constructed in Figure 1.
The barrel of the gun is marked 6, and its breech is closed by breech block 7
in the usual manner. The gun, as will be seen, is rifled from the shell chamber to
the muzzle which rifling is indicated by 8, and may be of any approved style, but
is preferably of increasing twist towards the muzzle of the gun.
The projectile has a cylindrical shell 9 which is of a smaller diameter than the
rifled portion of the gun for which the projectile is designed. At the front end of
the projectile its shell is of increased thickness, and forms a guide band 10, which
is of suitable diameter so as to fit snugly between the ribs or land portions of the
rifled bore of the gun.
A compression band 11 is securely fitted and held in a

page_text: groove which is cut in the guide band 10. This compression band is of any
approved construction and is adapted to impart an axial spinning motion, to the
projectile by engaging the rifling of the gun in the usual manner. The guiding
lugs 12 are projections on the cylindrical shell 9, located in the rear of the guide
band and keep the projectile centrally located within the gun, thereby permitting
the propelling gases to completely envelope the same. In the rear end portion
of the shell, a metallic collar 13 is secured, leaving a central or axial opening 15 in
the rear end of the shell, thus allowing the propelling gases to act against the
plunger 16, which in turn acts upon the contents of the shell, transmitting the
pressure through the fluid body 17 outwardly upon the shell and equally throughout
its length. A detonator case 18 is secured, preferably in the head of the shell, as
shown in Figure 5. This case should be of sufficient strength to withstand the
pressure of the propelling gases. The detonator or fuse may be of any approved
construction. The priming charge of dry gun-cotton 19 is placed in the detonator
case and thus protected from the heat generated by the propelling gases and also
from undue pressure or shock.
The wet gun-cotton 20 is preferably packed in cartridges 21, which are
hermetically sealed, thus insuring the stability of the explosive.
It will be observed that the shell of the projectile is open at its rear end or
base, thus allowing the force of the propelling charge to exert itself on the plunger
and through it upon the mass of wet gun-cotton. At the same time, the pressure
caused by the explosion of the propelling charge envelopes the greater portion of
the shell, thus counterbalancing the interior pressure and preventing the bulging
of the shell and its jamming within the gun. The shell of the detonator case is
of ample strength to withstand the full pressure of the expelling charge without
fracture.
The liquid body enclosed between the interior of the shell of the projectile aud
the exterior of the cartridges containing the explosive material, prevents heating
of the cartridge shells and also serves as a medium for equalizing the pressure
from within and counter-balancing the pressure from without. The head or
outward portion of the shell must be made of increased thickness and strength,
because at no time while the shell is within the gun is there any external pressure
effective upon that portion of the shell forward of the rear part of the compression
band. As the head of the shell issues from the gun, there will, of course, be a
slight waste of the force of the expelling charge, which waste is due to the fact
that the shell of the projectile to the rear of the compression band is of less
diameter than the rifled bore of the gun, but while the head of the shell is as yet
within the gun, there is not any leakage of gases as the compression band fitting as
it does to the contour of the gun rifling confines the full force of the propelling
gases within the gun, while the guiding lugs insure the axial position of the shell.
It is obvious that modifications of my invention can be made. For example, the
shell may be loaded in a different manner; the compression and guide band may
be otherwise constructed; an expansion band may be used in place of the compression
band, or the shell may be so fitted as to be serviceable for smooth bore guns. By
locating the guide band at the front end of the shell instead of on the rear portion
thereof, as heretofore where a single guide band is used, and by employing guide
lugs with openings between them, the expelling gases may freely envelope the
whole of the main body of the shell. The guide lugs may in some instances be
omitted by making the rifling of special form, as for example, with the ribs or land
portions narrow so as to restrict the contact surface to narrow lines.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what f
claim is :-
1. The improved construction in explosive shells or projectiles, substantially as
herein shown and described for the purpose stated.
2. An explosive shell having an open base, a compression band located on the

page_text: forward end portion of the shell and guide lugs on the body of the shell in the rear
of said band, for the purpose specified.
3. The herein described improvement in projectiles comprising in combination a
principal shell, and a sealed shell or shells containing high explosives arranged
within the interior of the principal shell, a liquid body filling the interstices
between the shells, a liquid seal and an open ring or spider confining the explosives
within the shell and permitting the gases of the expelling charge to enter the
interior thereof, substantially as and for the purpose described.
Dated this 13th day of October 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.