Improvements in Percussion Fuses for Projectiles.
Year: 1892

page_text: Date of Application, 14th Dec., 1892
Complete Specification Left, 16th Oct., 1893-Accepted, 14th Mar.. 1894
RUVIDIONAL SPECIFICATION.
Improvements in Percussion Fuses for Projectiles.
I, HENRY COOPER SEDDON of 4 Colinett Road, Putney, in the County of
Surrey, Retired Colonel in Her Majesty's Service do hereby declare the nature of
this invention to be as follows:-
The object of my invention is to produce a safety percussion fuse that shall be
self-acting and very sensitive but not liable to detonate until the projectile to
which it is applied has been suddenly checked in its flight after quitting the bore
of the gun.
For this purpose according to my invention forward movement of the detonating
pellet is prevented by means of a piece or pieces of some suitable hard substance
(it may be metal) retained in place until released by the freeing and setting back
of a gas tight stopper or cover that is normally attached to the base of the fuse but
is adapted to be unfastened therefrom by the action upon the fastening device of
the gases within the bore of the gun after leaving which the said gas tight stopper
or cover is relieved from the gas pressure so that it may be set back or retired to
free the piece or pieces of hard substance that would otherwise oppose the forward
movement of the denotating pellet in relation to the body of the fuse on sudden
checking of the flight of the projectile. Any suitable means (for example springs)
may be employed to ensure the necessary setting back or retirement of the gas
tight stopper or cover.
In order to prevent the creeping forward of the detonating pellet during the
flight of the projectile the said pellet is constructed with parts adapted to serve as
friction pieces against the inside wall of the pellet chamber during the rotary
motion of the projectile, but to move forward with the detonating pellet when the
projectile has been suddenly checked in its flight.
In order that the detonating pellet may easily advance when the flight of the
projectile is suddenly checked, the detonating pellet is provided with axial
extensions or ends mounted in holes that serve as fore and aft bearings in such wise
that the circumference of the main body of the detonating pellet is kept out of
actual contact with the wall of its containing chamber.
In one arrangement the rearward hole is formed in a diaphragm that constitutes
a rearward closure to the containing chamber. Through this diaphragm air holes
are formed which may be kept normally closed by the pieces of hard substance
which serve to prevent the forward movement of the detonating pellet and which
in this instance may be of spherical form and are held against the outer surface of
the diaphragm over the ends of the holes by a flange or head formed on the
rearward axial extension of the detonating pellet.
In order to render the forward closure of the detonating chamber water-tight
whilst at the same time enabling passages to be readily formed therethrough on the
occurrence of an explosion within the said chamber, I form the said closure with
holes extending from the inner surface thereof partly but not entirely through the
thickness of the closure, leaving a sufficient thickness of material to form an
efficient water-tight closure without offering undue resistance on the occurrence of
the explosion.
It will be understood that in a fuse constructed with a gas tight stopper or cover
adapted to be released according to my invention the pressure in the gun tends to
increase and preserve the safety of the fuse against premature explosion.

page_text: It is to be remarked that in the construction of fuses according to my invention
some of my improvements may be adopted without the others.
Dated this 13th day of December 1892.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C.
Improvements in Percussion Fuses for Projectiles.
1, HENRY COOPER SEDDON of 4 Colinett Road, Putney, in the County of
Surrey, Retired Colonel in Her Majesty's Service, do hereby declare the nature
of this invention and in what manner the same is to be performed to be par-
ticularly described and ascertained in and by the following statement :―
The object of my invention is to produce a safety percussion fuse that shall be
self-acting and very sensitive, but not liable to detonate until the projectile to
which it is applied has been suddenly checked in its flight after quitting the bore
of the gun.
For this purpose according to my invention, forward movement of the detonating
pellet is prevented by means of a piece or pieces of some suitable hard substance,
metal balls by preference, retained in place until released by the freeing and setting
back of a gas tight stopper or cover that is normally attached to the base of the
fuse but is adapted to be unfastened therefrom by the action upon the fastening
device of the gases within the bore of the gun after leaving which the said gas
tight stopper or cover is relieved from the gas pressure so that it may be set back
or retired to free the piece or pieces of hard substance that would otherwise oppose
the forward movement of the detonating pellet in relation to the body of the fuse
on sudden checking of the fight of the projectile. Any suitable means (for
example springs) may be employed if desired, to ensure the necessary setting back
or retirement of the gas tight stopper or cover. With the constructions of fuses
hereinafter described no such special means for this purpose, are considered
necessary though they may be added if desired.
In order to prevent the creeping forward of the detonating pellet during the
flight of the projectile, the said pellet is constructed with parts adapted to serve as
friction pieces against the inside wall of the pellet chamber during the rotary
motion of the projectile, but to move forward with the detonating pellet when the
projectile has been suddenly checked in its flight.
In order that the detonating pellet may easily advance when the flight of the
projectile is suddenly checked, the detonating pellet is provided with axial exten-
sions or ends mounted in holes that serve as fore and aft bearings in suchwise
that the circumference of the main body of the detonating pellet is kept out of
actual contact with the wall of its containing chamber.
.
It will be understood that in a fuse constructed with a gas tight stopper or cover
adapted to be released according to my invention, the pressure in the gun tends to
increase and preserve the safety of the fuse against premature explosion.
In the accompanying drawings,
Fig. 1 shows partly in central longitudinal section and partly in elevation, to an
enlarged scale, a percussion fuse constructed according to this invention, the section
being taken on the line AA of Fig. 2.
Fig. 2 is an elevation of the base end thereof.
Figs. 3, 4, 5 and 6 are cross sections on the lines a a, b b, c c, and dd, respectively
of Fig. 1.
The body of the fuse, which may advantageously be made of manganese bronze,
consists of an externally screw-threaded portion 1 adapted to be screwed into the

page_text: base of a projectile, and an enlarged base portion 2 having a conical shoulder 3
adapted to bear against a corresponding shoulder in the base of the projectile and
thereby assist in taking the pressure of the gas upon the base of the fuse. Internally
the body of the fuse is formed with two chambers, namely, a cylindrical pellet
5 chamber 4, and a conical ball chamber 5, these two chambers being separated by a
wall or diaphragm 6 through which a series of air holes 7 are formed. 8 is a
centrally perforated metal disc or plate screwed into the forward end of the body
of the fuse and forming the forward end wall of the pellet chamber.
The detonating pellet, which may advantageously be made of Muntz metal,
comprises a pin 9 formed with three collars 10, 10 and 10%, the former one, 10,
being made of small size so as to form a distance piece to prevent the pellet setting
back and closing the air holes 7 in the diaphragm 6, and the two latter being
arranged at a suitable distance apart so as to form an annular space for the recep-
tion of a friction device, and being of such a diameter as to just run clear of the
inner side of the pellet chamber. The ends of the pin are carried and guided
by the diaphragmn 6 and disc or plate 8, and are made of cylindrical form in
order that the pellet may have greater freedom of movement, than otherwise,.
in an endways direction, when subjected to a transverse blow caused by a graze
contact. The rear or tail end of the said pin is formed with an annular groove II
of circular shape in cross-section, and its forward end is provided with a firing
needle 12 that may be of steel. The friction device between the collars 10*
and 10 consists, in the example shown, of a loose metal ring 13 made in two
halves that can fly apart under the action of centrifugal force during the flight.
of the projectile to which the fuse is attached, and bear with more or less force,
according to their weight, against the inner side of the pellet chamber, and thereby
prevent any forward movement of the pellet during flight, but on the projectile
receiving the slightest check they will slide forward and add their momentum to
that of the detonating pellet and thereby ensure the effective action of the latter.
14, 14 are balls arranged within the chamber 5 and adapted to fit into the
groove 11 in the tail end of the pin 9 so as to prevent the detonating pellet moving
forward until after the projectile has been fired. The fore end of the ball chamber
may advantageously be made slightly concave, as shown, so that the balls will tend
to assemble around and fit into the groove in the tail end of the pin 9 when vertical
or approximately 60. The balls, which may advantageously be made of manganese
bronze or nickeled steel, are normally, held in place in the groove 11 by a
conical stopper or cover 15 (hereinafter called a stopper) that fits gas tight
within the rearward extension of the conical ball chamber and is recessed at its
fore end to receive the tail end of the pin 9 but without touching it and also to
surround the series of balls 14 sufficiently to retain them in the groove 11 as
shewn. The said stopper is normally attached by its rim 15 to the base 2 by
fastening screws 17 of which there are three in the example shown. The head
of each of these screws is located within a hole 18 in the said rim so
as to be protected against accidental blows; the thickness of the portion 15 of
metal forming the bottom of the said hole against which the head of the screw
rests, and the length and depth of the screw thread 19 are so related that the
said portion of metal will be sheared and the screw thread stripped by the gas
pressure, acting on the head when the gun is fired. To receive the sheared
portions of metal 15 and the screw heads there are formed in the base cylindrical
recesses 19, each coaxial with but of slightly larger diameter than the corre-
sponding hole 18 and there are cavities 19b to receive the ends of the stripped
Screws when driven forward by the gas pressure upon the screw head. To assist
the shearing action above referred to annular grooves or nicks may be formed
at 15.
20, 20, are check screws that may be employed to prevent the stopper becoming
disconnected from the fuse when it moves back to free the balls 14. Each check
crew is made with a head that is partly formed with a screw thread and is
bartly conical; also with a plain stem having its free end enlarged and formed

page_text: with a screw thread which is screwed through a screw threaded hole 21 into a
cavity 22, sufficiently far to afterwards allow of the desired rearward movement
of the stopper which will be arrested by the enlarged inner parts of the screws
coming into contact with the rear end walls of the cavities 22.
It will be understood that the heads of the screws are screwed into the screwed
holes formed in the rim 15 of the stopper to receive them as shewn, the
conical parts extending also into cavities formed in the base. By extending the
heads of the check screws into the base, as shewn, twisting of the stopper and
rim are also obviated.
On opposite sides of the rim are slots 23 arranged in line with corresponding
Elots formed in the base of the fuse so as to permit of a suitable key or spanner
being inserted into the latter slots for the purpose of screwing the fuse into the
base of a projectile.
24 is a screw plug or closure screwed into the forward end of the body of the
fuse. It is formed with a powder or detonating chamber 25 closed by a centrally
perforated disc or plate 26 in which is a chamber or recess 27 to receive the
detonating cap which is held in place by a ring 28 screwed into the said disc
or plate.
In order to render the forward end or closure of the detonating chamber
water-tight, whilst at the same time enabling passages to be readily formed there-
through on the occurrence of an explosion within the said chamber, I form the
said plug or closure, with one or more holes 24" extending from the inner surface
thereof partly but not entirely through the thickness of the closure, leaving a
sufficient thickness of material to form an efficient water-tight closure without
offering undue resistance on the occurrence of the explosion.
If the detonating chamber is kept separate from the body of the fuse, its rear
end can be closed by a water tight disc, plug, or other suitable device.
The action of this fuse, is as follows:-On discharging a gun containing a
projectile fitted with such a fuse the fastening screws 17 are driven inward,
shearing the thin portions of metal 15 stripping the screw threads 19ª and
freeing the stopper 15 which however is held tightly in place by the gas pressure
until the projectile has left the gun.
During the flight of the projectile a partial vacuum is formed at its base.
This causes the air within the fuse to expand and assist in pushing the stopper
back, whilst the balls 14, holding the tail end of the detonating pellet, at once
fly outward and assist in pushing the stopper rearward. The detonating pellet
is then free to move forward, but is checked during flight by the two halves of
the centrifugal ring 13 clinging to the inner surface of the pellet chamber. On
graze or impact of the projectile, the centrifugal ring moves forward with the
body of the pellet, and causes the firing needle 12 to strike the detonating cap,
thus firing the fine-grained powder in the detonating chamber, which, in exploding,
bursts through the thin metal at the outer ends of the recesses 24 and fires the
projectile.
In the modified construction of fuse shown in Figs. 7 and 8, which are similar
views to Figs. 1 and 2 respectively, the conical gas tight stopper 15 is provided
at its outer side with a central pin 15ª, and is normally held in place, so as to
retain the centrifugal balls 14 in the groove 11, by a disc shaped pressure
plate 29. This pressure plate, which may be of manganese bronze, is made
with a central recess 29 on its inner face to receive the pin 15 on the stopper,
and is held in place by a base plug 30. This plug, which may also be made of
manganese bronze, is screwed into the base 2 of the fuse, and is formed with
longitudinal holes 31, and it may be also with lateral holes 31" running into the
enlarged inner portion of the central hole 31 communicating with a circular
recess 32, in order to allow the gas pressure produced in the gun, from which the
projectile is fired, to act upon the pressure plate 29. The said holes may be
covered, at one or both ends, with suitable waterproof material to render the base
plug both air and water tight. Or the inner ends of the said holes may be closed,

page_text: for the purpose mentioned, by a disc 32" of metal, forced into the circular
recess. 32 on the inner side of the base plug 30.
33 is a cup shaped gas check.
It is formed of thin metal, such as sheet copper,.
with a central hole to fit over the pin 15 on the stopper, and is arranged to be
driven home against the stopper by the pressure plate. This gas check affords an.
additional precaution against the stopper 15 moving back prematurely, but its use.
is not considered essential. When it is used, the pressure plate, instead of being
merely recessed at 29" so as to leave a thin portion of metal at 29b to be sheared
through by the pin 15 when the pressure plate is forced inward by the gas pressure,!
may be perforated so that when it is forced inward it passes freely over the pin, in
which case I should further raise the central portion of the gas check sufficiently
to allow the central portion of the pressure plate to take a bearing on it. I prefer
however, for the sake of greater safety, to only recess the said pressure plate as-
shown.
The base 2 of this modified construction of fuse is shown as formed with a square-
shoulder at 3 to receive a lead or other soft metal gas ring 3ª, but it may be formed
with a conical shoulder as in the first example if preferred.
The action of this modified construction of fuse is as follows:-
On discharging the gun, the gas pressure passing through the holes 31 and 31%
in the base plug 30, drives the pressure plate 29 down on to the head of the conical
stopper 15, shearing out the portion 29b, and at the same time forcing the
check 33, if used, tight down onto the head of the stopper and outwards against
the sides of the conical chamber, so leaving room for the stopper to set back.
gas.
After the projectile has left the gun, the setting back of the stopper, the bringing
into action of the friction device 13, and the subsequent moving forward of the
pellet and firing of the projectile, take place in the manner hereinbefore explained
with reference to the construction of fuse shown in Figs. 1 to 6 inclusive.
The pellet chamber 4 instead of being made cylindrical, as in the examples.
hereinbefore described, may be made slightly conical as shown in central
longitudinal section in Fig. 9, so as to assist in preventing premature movement of
the pellet during flight and the outer periphery of the divided friction ring 13 may,.
in that case, be made convex in cross section as shown.
Fuses constructed as herein before described possess many important practical
advantages. They will withstand the roughest usuage with safety. Premature
explosion in a gun, even should the projectile be checked in its passage through
the bore, is rendered impossible, as also is premature explosion during the flight of
the projectile. They will act on the slight graze of the projectile against an object.
outside of the gun. They are applicable to various classes of projectiles, including
quick firing ammunition, and also to various types of guns, whether using quick or
slow burning explosives. They admit of projectiles in which they are fixed being
carried about ready fused with perfect safety, and are less liable than ordinary
fuses, as heretofore constructed, to deteriorate by storage, owing to their being
completely air and water tight. Their detonating cap and powder chambers being
formed in a detachable plug, they need not be charged until required for use..
Furthermore they are simple in construction and therefore comparatively cheap to
make.
It is to be remarked that in the construction of fuses according to my invention,.
some of my improvements may be adopted without the others.
Having now particularly described and ascertained the nature of the said inven--
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. A percussion fuse for a projectile in which the device that holds the balls or
equivalent employed to prevent forward movement of the detonating pellet in
relation to the body of the fuse is unfastened by the pressure in the gun, but is by
such pressure caused to retain the pellet until after the projectile has left.
the gun.

page_text: 2. A percussion fuse for a projectile in which forward movement of the detonating.
pellet in relation to the body of the fuse is prevented by balls held by a gas tight
stopper or cover fixed to the body of the fuse in such a manner that on the firing
of the gun the gas pressure in the gun will unfasten the stopper or cover but will
act to keep it in place in the fuse body so as to hold the balls and detonating pellet
until the projectile has left the gun.
3. A percussion fuse for a projectile in which the detonating pellet is constructed
with parts such as 13 adapted to act under the influence of centrifugal force, due
to rotation of the projectile, as friction pieces against the wall of the pellet
chamber, so as to prevent the pellet creeping forward during flight of projectile,
but to release the pellet when forward movement of the projectile is suddenly
checked as set forth.
4. In a percussion fuse for a projectile, the combination with a fuse body and
detonating pellet, of means such as described for holding the pellet fast in its
chamber until the projectile has been fired from a gun, and the frictional device for
preventing forward movement of the pellet in relation to the fuse body during
rotation of the projectile, as set forth.
5. In a percussion fuse for a projectile, a detonating pellet constructed with parts
adapted to act as friction pieces, as referred to in the preceding claim, and provided
with axial extensions or ends mounted in holes that serve as fore and aft bearings
in such a way that the circumference of the main body of the pellet is kept out
of actual contact with the wall of its containing chamber, substantially as herein
described for the purpose specified.
6. In a percussion fuse for a projectile, a water-tight detonating chamber formed
in a plug or closure the forward end of which is constructed with a part or parts
of less thickness than the remainder (as at 24") substantially as described for the
purpose specified.
7. The construction of percussion fuse for projectiles, substantially as herein-
above described with reference to and illustrated by Figs. 1 to 6 inclusive of the
drawings.
8. The modified construction described with reference to Figs. 7 & 8.
9. The modified construction described with reference to Fig. 9.
Dated this 14th day of October 1OOD.
W. Lloyd Wise,
H. C. SEDDON.
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.