IMPROVEMENTS IN FUSES FOR PROJECTILES
Year: 1879

page_text: LETTERS PATENT to Charles Ambrose McEvoy, of 18, Adam Street, Adelphi,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN FUSES
FOR PROJECTILES."
Sealed the 24th October 1879, and dated the 27th June 1879.
PROVISIONAL SPECIFICATION left by the said Charles Ambrose McEvoy at
the Office of the Commissioners of Patents on the 27th June 1879.
CHARLES AMBROSE MCEVOY, of 18, Adam Street, Adelphi, in the County of
Middlesex. IMPROVEMENTS IN FUSES FOR PROJECTILES."
"
According to this Invention I form a percussion fuse in such a manner that it
can be carried at the base of a hollow projectile in place of at its front and, as
heretofore.
For this purpose I form the outer case of the fuse of a short metal cylinder with
a screw thread on its exterior to screw into a corresponding screw thread in a hole
at the base of the projectile; this hole leads into the inner chamber of the projectile,
which contains the bursting charge. Around the rear end of the case, which is
solid, is a projecting flange to come against the base of the projectile. The forward
end of the cylindrical case is closed by a short plug of metal screwed into it. At
the centre of the inner end of this plug is a conical projection forining a nipple, on
to which an ordinary percussion cap may be placed. A hole is bored through the
nipple and through the centre of the plug, so that when the cap is exploded the
flash may pass to a small quantity of powder contained in a recess in the forward
end of the plug, and be so transmitted to the bursting charge of powder in the
interior of the projectile. Over the small quantity of powder in the recess in the
front of the plug is placed a thin disc of metal foil, and the edge of the inner end of
the cylindrical case is turned inwards over the disc to retain it in place. Within
the interior of the cylindrical case is a solid metal striker or hammer; through the
forward end of the striker or hammer is passed a wire pin. The projecting ends
of this pin rest against the end of a safety cylinder, which at its forward end rests
against the rear end of the plug before mentioned, and so the striker or hammer is
prevented from coming against the cap on the nipple. When however the pro-
jectile is fired from a gun the safety tube shears off the projecting ends of the wire
pin and moves back over the stem of the hammer, and gets jammed on to it by

page_text: reason of the rear end of the stem of the hammer being slightly tapered qutwards.
When the projectile strikes any obstacle the hammer with the safety tube adhering
to it flies forward and strikes the cap, and so the fuse is fired.
If desired a safety pin may be passed through the rear end of the outer cylindrical
case and also through the hammer, to securely hold back the hammer and prevent
all chance of an accidental ignition of the fuse. In this case when the projectilo
is to be used the safety pin will require to be withdrawn, and the fuse may be
then screwed home tightly into its place at the base of the projectile.
In place of using an ordinary percussion cap the forward end of the hammer
may have a small recess formed in it to contain fulminating compound. The nipple
in this case would be replaced by a small point for the fulminate carried by the
hammer to strike against, and small holes would be formed, starting from the base
of the pin, for the flash to pass to the powder at the forward end of the fuse.
By constructing percussion fuses in the above manner the hammer to effect
ignition is thrown forwards towards the bursting charge of the projectile in place
of being thrown forwards away from the bursting charge, as is the case in ordinary
percussion fuses, which are carried at the forward end of a projectile, and so a
more direct action is obtained, and the necessity of forming a passage lengthwise
through the hammer for the flash to pass through backwards is obviated. Also by
constructing the fuse so that it may be carried at the base of a projectile, the for-
ward head of the projectile may be left solid; this is especially of advantage for
hollow projectiles of comparatively small dimensions.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Ambrose MoEvoy in the Great Seal Patent Office on the
24th December 1879.
CHARLES AMBROSE M°EVOY, of 18, Adam Street, Adelphi, in the County of
Middlesex. "IMPROVEMENTS IN FUSES FOR PROJECTILES."
According to this Invention I form a percussion fuse in such a manner that it
can be carried at the base of a hollow projectile in place of at its front end, as.
beretofore.
For this purpose I form the outer case of the fuse of a short metal cylinder with.
a screw thread on its exterior to screw into a corresponding screw thread in a hole
at the base of the projectile; this hole leads into the inner chamber of the projectile,
which contains the bursting charge. Around the rear end of the case, which is
solid, is a projecting flange to come against the base of the projectile. The forward
end of the cylindrical case is closed by a short plug of metal screwed into it. At
the centre of the inner end of this plug is a conical projection forming a nipple, on
to which an ordinary percussion cap may be placed. A hole is bored through the
nipple and through the centre of the plug, so that when the cap is exploded the
flash may pass to a small quantity of powder contained in a recess in the forward
end of the plug, and be so transmitted to the bursting charge of powder in the
interior of the projectile. Over the small quantity of powder in the recess in the
front of the plug is placed a thin disc of metal foil, and the edge of the inner end
of the cylindrical case is turned inwards over the disc to retain it in place. Within
the interior of the cylindrical case is a solid metal striker or hammer; through the
forward end of the striker or hammer is passed a wire pin. The projecting ends
of this pin rest against the end of a safety cylinder, which at its forward end rests
against the rear end of the plug before mentioned, and so the striker or hammer is
prevented from coming against the cap on the nipple. When however the pro-
jectile is fired from a gun the safety tube shears off the projecting ends of the wire
pin and moves back over the stem of the hammer and gets jammed on to it by
reason of the rear end of the stem of the hammer being alightly tapered outwards.
When the projectile strikes any obstacle the hammer with the safety tube adhering
to it flies forward and strikes the cap, and so the fuse is fired. If desired a safety
pin may be passed through the rear end of the outer cylindrical case, and also
through the hammer, to securely hold back the hammer and prevent all chance of
an ignition of the fuse. In this case when the projectile is to be used the safety
pin will require to be withdrawn, and the fuse may then be screwed home tightly
into its place at the base of the projectile.
In place of using an ordinary percussion cap the forward end of the hammer may
have a small recess formed in it to contain fulminating compound.
The nipple in this case would be replaced by a small point for the fulminate
carried by the hammer to strike against, and small holes would be formed, starting
from the base of the pin, for the flash to pass to the powder at the forward end of
the fuse.
By constructing percussion fuses in the above manner the hammer to effect
ignition is thrown forwards towards the bursting charge of the projectile in place
of being thrown forwards away from the bursting charge, as is the case in ordinary
percussion fuses which are carried at the forward end of a projectile; and so a
more direct action is obtained, and the necessity of forming a passage lengthwise
through the hammer for the flash to pass through backwards is obviated. Also by
constructing the fuse so that it may be carried at the base of a projectile, the
forward head of the projectile may be left solid; this is especially of advantage for
hollow projectiles of comparatively small dimensions.
The Drawing hereunto annexed shows a hollow projectile fitted with a fuso at
its base, as above described.

page_text: Figure 1 shews a longitudinal section of the projectile and fuse ready for firing;
Figure 2 is a similar view of the rear end of the projectile, shewing the moveable
safety pin in position for holding back the hammer. In many cases the use of this
safety pin may be dispensed with.
A is the projectile, and A* a cavity within it for containing an explosive charge;
B is the fuse case screwing into a hole in the base of the projectile; C is the pro-
jecting flange or collar around the base of the fuse case. When the fuse is screwed
home this collar forms a firm support for the fuse when the projectile is fired from
a gun, and effectually prevents all passage of gas to the bursting charge of the pro-
jectile, and also assists in preventing the fuse case from being blown inwards into
the cavity of the projectile; it may also, as shewn in the Drawing, serve to secure
a gas check to the base of the projectile. D is the plug which screws into and
closes the front end of the fuse case B; E is the nipple formed on the inner side of
the plug, and which is to carry a percussion cap, as before described; F is a cavity
in the forward end of the plug containing gunpowder or other explosive compound;
G is a disc of thin metal closing the front of the cavity F. The edge of the end of
the case B is turned inwards, as shewn, so that it overlaps the edge of the disc and
holds it in place. H is the striker or hammer contained within the interior of the
case B; I is the small wire passed through the forward end of the striker ; K is the
safety tube, against which the projecting ends of the wire I rest.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I an aware that a loose safety tube and
small wire pin passed through the hammer or striker of a fuse have before been
used for preventing the hammer or striker from striking against and exploding the
percussion cap or detonator of a fuse carried at the forward end of a projectile;
I therefore lay no claim to such mode of holding back the hammer until the time
when the projectile is fired from a gun, but I claim,-
First. Forming the percussion fuses of projectiles in such a manner that they are
to be carried at the base instead of at the front end of the projectile, as herein before
described.
Second. The construction of percussion fuses for projectiles as hereinbefore
described and illustrated in the Drawing annexed.
In witness whereof, I, the said Charles Ambrose McEvoy, have hereunto set
my hand and seal, this Twenty third day of December, in the year of our
Lord One thousand eight hundred and
C. A. M'EVOY. (L.S.)