Improved Means for Igniting the Charge Contained in Explosive Projectiles.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improved Means for Igniting the Charge Contained in Explosive
Projectiles.
1, WILLIAM KENNISH, of Brooklyn, King's County, New York, United States
of America, Mechanician, 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 :-
This invention relates to devices for igniting the charge contained in explosive
projectiles and is applicable either to those projectiles which burst at a pre letermined
time after leaving the gun (commonly called timed shells) or to percussion shells.
The objects of this invention are to insure the bursting of the shell or projectile
by rendering certain the ignition of the charge, and, at the same time, to permit
the shells to be handled with safety by preventing premature ignition.
:
In the accompanying drawings, Fig. 1 is a sectional view of a part of a conical
projectile or timed shell for a rifled gun and made in accordance with the present
invention Fig. 1ª being a sectional view, on a smaller scale, of the entire projectile,
illustrating the way in which it is preferred to construct the body and sabot.
Fig. 1 is an end elevation of the butt of the projectile shewing the undercut cross
grooves for the reception of the soft metal sabot. Fig. 2 is a transverse section
through the tip of the projectile in the plane indicated by the dotted lines in Fig. 1.
Fig. 2 is a perspective view of the friction-piece and detent. Fig. 3 illustrates the
substitution of a percussion igniter for the friction igniter shewn in Figs. 1 and 2.
Figs. 4 and 5 shew the application of this invention to a percussion shell or projectile
which bursts on striking with sufficient force against an object tending to arrest its
forward and rotary motion. Figs. 6, 7 and 8 illustrate slight modifications in
construction.
1 will first describe Figs. 1, 2 and 2, premising that this invention is adapted only
for elongated shells fired from rifled guns, as the axial rotation of the projectile is
relied upon for effecting the operation of the improved fuse or igniter.
a represents the front end of the body of the shell, the chamber of the shell being
filled with powder or other suitable explosive which forms the bursting charge. The

page_text: front end of the powder-chamber is closed by a cross partition, and, in an aperture
in this partition, is fixed a time fuse which need not be special in character. In
the body of the shell is screwed a removable brass plug or cap c, which constitutes the
conical tip of the shell. The cap c is provided with a suitable aperture or apertures c*
to admit air within the cap to the chamber over the outer end of the fuse b. A
stud or screw d, through which the axis of the projectile passes, is set tightly in the
inner face of the cap c. On the screw-threaded shank of the screw d is rotatively
mounted a part e, hereinafter called the wheel. The latter is, preferably, in the shape
of a hemisphere hollowed out on its inner side, as this form provides the desirable
maximum weight for a given diameter. The wheel should rotate freely on the screw.
Projecting inwardly from the wheel-rim is a fixed friction igniter g. which may be of
almost any kind; as, for example, a short stem inserted in a socket in the rim of the
wheel and provided on its projecting end with a charge of fulminate or other sub-
stance capable of being readily ignited by friction.. An ordinary Vesta, for example,
with a shortened stick, may serve the purpose.
On the inner face of the cap c, near its base, is secured a bracket h, shewn
separately in Fig. 2*. The bracket carries the friction-plate * and the spring-
detent, and is so situated with reference to the igniter g, that, when the shell a
rotates in the direction of arrow y (Fig. 2), the wheel e remaining stationary, the
roughened surface of the plate 4* is brought into contact with and fires the fulminate
on the igniter g. The flame from the igniter is instantly communicated to the inner
end of the time-fuse b, the latter in due course firing the bursting charge in the
powder-chamber of the shell.
The operation of the parts is as follows :-
:-
Suppose the battery is firing "five seconds" shells. The gunner removes' the
cap c from the projectile, cuts the fuse to "five seconds," places an igniter 9 in the
socket in the wheel e, and turns the said wheel to the position seen in Fig. 2. The
spring, which forms the detent, then presses on a slight protuberance e¹ on
the inner face of the rim of the wheel e in order to prevent accidental rotation of
the wheel on the screw d during the further manipulation of the projectile, which is
then ready to be placed in the gun. When the latter is discharged, the rifling causes
the projectile to rotate rapidly about its axis, but the inertia of the freely-mounted.
wheel e prevents it rotating therewith, and consequently the first revolution of the
shell, which is usually completed as the projectile leaves the muzzle of the gun, effects
the disengagement of the detent h², the piece h being then carried round so that the
roughened plate is brought into frictional contact with and fires the igniter g.
Thus the fuse bis ignited about the time the projectile leaves the muzzle of the
gun, the bursting charge being fired five seconds later.
If desired, the ignition of the time-fuse niay be effected by percussion instead of
friction. Under such circumstances, the only modification required is that illustrated
in Fig. 3. Instead of a friction-igniter, an L-shaped nipple i, on which is placed
a percussion cap, is inserted in the socket in the wheel e. When the projectile
has nearly completed a revolution, the cap is struck by an anvil or hammer j
carried by the bracket h in substitution for the roughened plate h*.
When the invention is applied to a so-called percussion shell, or shell which is
designed to burst upon striking the object aimed at, the wheel e is set so as to
act in a manner opposite to that just described. In Figs. 4 and 5 is illustrated the
application of this invention to a projectile of the character referred to.
The gunner, in preparing a shell of this kind for firing, screws back the wheel e
until it is in contact with and stopped by the head of the screw d. The igniter g
and the bracket h are then in the relative positions seen in Fig. ; the detent h¹
holding the wheel against accidental displacement.. The rotation of the projectile
when fired tends to tighten the head of the screw d against the wheel e, the latter
being consequently carried round with the shell, so that, during the flight of the
projectile, the bracket and the igniter g maintain the same relative position.
When, however, the projectile strikes the object aimed at, its rotary and forward
motions are retarded, such retardation causing the freely-mounted wheel e, owing to

page_text: the mementum acquired, to rotate independently on the screw d in the same
direction as that in which the projectile was rotating, whereby the igniter g is
brought into frictional contact with the plate h* and fired. The igniter, in the
illustration, is arranged to fire the bursting charge directly; the latter being
thus instantly exploded.
It will be seen that, in the case just described, the momentum acquired by the
wheel e consists of forces which tend to carry it in a forward direction and to cause
it to rotate; each force serving to assist the other in effecting the rotation of the
wheel for the purpose of firing the igniter.
The percussion device illustrated in Fig. 3 may be applied to the form of projectile
just described, as well as to that shewn in Figs. 1 and 2.
In Figs. 1 and the igniter g is for convenience of illustration shewn in a different
position to that represented in Figs. 2 and 5.
Figs. 6 and 7 correspond respectively with Figs. 1 and 2 and illustrate a modification
in which the shank of the stud or screw d is not screw-threaded (the wheel e having,
consequently, no longitudinal motion thereon) and the igniter g projects radially
outwards instead of inwards. Fig. 8 shews a further modification in which the
igniter. g projects from the under side of the wheel e. These views are merely
designed to illustrate some of the many ways in which the arrangement of the
elements constituting the present invention may be varied. In the construction
illustrated in these figures, the movement which upon the sudden stoppage of the
flight of the projectile is imparted to the wheel e owing to the shank of the stud d
being screw-threaded is entirely lost; so that, when, as under the present, circum-
stances, the shank of the screw is left smooth, reliance must be placed entirely on the
cessation or retardation of the rotation of the projectile.
It is obvious that the positions of the igniter and the device for firing the same
(whether it be an anvil or friction-plate) may be interchanged; that is, the device
referred to may be carried by the wheel and the igniter by the body or the cap of the
projectile.
In Figs. 1 and 1 is shewn a projectile to which the igniter above described may
be applied. The body a is provided with a sabot ax made of lead, copper or other
soft metal, which is cast to or fitted in the undercut grooves in the butt. These
grooves are shewn in Fig. 1', which represents the end of the body a before the sabot
is put on. The impact in firing forces the metal sabot firmly into the undercut
grooves. The body of the projectile is so constructed that when burst it may be
broken up into pieces of predetermined size. This is effected by boring holes in
the body at uniform and suitable distances apart and filling the holes so bored with
leaden plugs a¹ (Fig. 1). The projectile is thus weakened along predetermined
lines of fracture. To prevent the plugs blowing out and thus allowing the bursting
charge to expend its force without fracturing the body a, the holes aforesaid are
undercut or have retaining grooves to hold the plugs firmly in place. The latter
form additional missiles to supplement the destructive effect of the projectile.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. The improved means for igniting the charge contained in explosive projectiles
arranged or operating substantially as set forth.
2. In a shell or projectile for use with a rifled gun, an igniting device comprising
a wheel mounted to rotate about the axis of the projectile, an igniter borne by either
the projectile or the wheel and means carried either by the wheel or the projectile for
firing the igniter by the independent rotation of the wheel.
3. In a shell or projectile having a hollow removable tip or cap, the combination
with the body of the projectile of a wheel mounted to rotate within the cap about the
axis thereof, the wheel and the projectile being respectively provided with an igniter
and a device for firing the same, whereby the explosive charge is ignited by the
independent rotation of the wheel.

page_text: 4. In a shell or projectile having a hollow removable tip or cap, the combination
with the body of the projectile of a wheel pivoted within the cap and fitted with a
holder for the igniter in its rim and means mounted in the projectile for firing the
igniter by the independent rotation of the wheel.
5. In a shell or projectile having a hollow removable tip or cap, the combination
with the body of the projectile of a wheel pivoted within the cap and provided with
means for firing an igniter and a detent for preventing accidental rotation of the
wheel.
6. In a shell or projectile fitted with a hollow tip or cap, the combination with the
body of the projectile of a wheel mounted to rotate on a stud projecting axially from
the cap, the stud being screw-threaded and the wheel tapped with a thread to
correspond, the wheel and the projectile being respectively furnished with means for
firing and with a holder for an igniter for directly or indirectly igniting the charge.
Dated the 3rd day of Anril 1880
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C.,
Agent for the Applicant.