Improvements in or appertaining to Percussion and Time Fuses for Firing Explosives.
Year: 1889

page_text: Date of Application, 2nd Nov., 1889
Complete Specification Left, 11th July, 1890-Accepted. 1st Nov. 1890
PROVISIONAL SPECIFICATION.
Improvements in or appertaining to Percussion and Time Fuses for
Firing Explosives.
I; ARNOLD WALTER, of 16, Rue Droust, Paris, in the Republic of France, do hereby
declare the nature of this invention to be as follows:-
This invention has for its object (inter alia) to simplify the construction of fuses, to
render their action more sure, to render their conveyance free from danger, and to
give the projectile in which the fuse is mounted that pointed shape necessary to give
a proper ballistic effect.
....
Apart from the improvements effected in the construction of percussion or time
fuses; this invention has besides for its object a double acting fuse characterised by
the combination of a percussion fuse and a time fuse, that is to say, a fuse acting
independently of any shock when a certain time previously determined has elapsed
after the discharge of the projectile from the cannon's mouth. This result is obtained
by the combination, with the priming and the stationary striker of the fuse, of a
channel into which powder has been first rammed, of which powder a quantity less or
greater must be consumed before the flame arrives at the communication channel
between the fuse and the body of the projectile to cause the explosion of the latter.
In a percussion fuse constructed in accordance with my invention, the body is
composed of an upper conical part, which forms, when in place, the point of the
projectile and of a threaded bush which is screwed into the mouth of the shell.
The upper part has two notches or recesses in which engage the teeth of the key
which is used to screw the fuse on the shell. The conical upper part carries inside a
screwed percussion appliance or stationary striker which is held up by a lead washer.
lodged in a groove prepared for this purpose with the object of preventing the
percussion appliance from being unscrewed of itself. The threaded bush forms in its
interior a receptacle for the safety tube with its different parts, and is closed at its
lower end by a perforated screw washer.
The safety tube is preferably made of copper suitably drawn out, and has several
tongues punched or bent down in its inside, the number of which may vary according
to the resistance required, as hereinafter explained. Each of the back row of tongues
has preferably the form of an isosceles triangle. the two cut out ends of which are
longer than the third on which the triangle is bent over. The front tongues have the
shape of a trapeze, the three sides of which are cut out and bent back on the fourth.
Between these two sets of tongues is situated a capsule of rolled copper (preferably
made by cutting out with a punch) and having inside a perforated lead cylinder. In
the front of this latter are placed the fulminating cap and explosive powder.
The capsule which is supported by the tongues aforesaid by reason of its inertia
tends to remain stationary during the shock of discharging, and it thus bends back
the tongues behind it which are too weak to resist and the capsule places itself on a
cardboard or other soft washer placed behind to receive it and break the shock. The
fuse is then ready for action and when the projectile is stopped by any obstacle,
the cap striking against the stationary striker ignites and communicates, through the
hollow cylinder and the washer, the flame to the explosive charge, thus bursting
the projectile.
In a time fusc constructed according to my invention, the body of the fuse
(preferably of bronze) is composed of a cylindrical part fitted with a screw thread for
the pressure screw and the knob or point, and of a screwed conical bush capable of
being screwed onto a shell. The body of the fuse is bored through its entire length
and contains, inside, the percussion arrangement composed of a safety tube with a
copper capsule, of the screwed stationary striker held by two lead washers and of a
011

page_text: priming of powder. A recess is made in the conical part for holding the powder, it
is connected with the outer part of the body of the fuse by a channel placed opposite
the spot where, outside, the projectile has a regulating or index pin. Above the
priming powder is placed a number of touch holes communicating with a fire groove
arranged near the outside of the body of the fuse.
The lock nut is preferably of bronze and furnished outside with flutings, it is bored
and threaded so as to be adapted to be screwed on the body of the fuse and adjusted
on the plate of the same by steel or other washer. The plate of the fuse is preferably
of brass, and circular in shape, it has at its lower end a groove coated with tin in
which is rammed a ring of powder, interrupted in its circuit by a sort of bridge
between which and the commencement of the ring an opening is made for receiving
the firing arrangement formed of compressed powder covered outside by a disc.
The external conical edge of the fuse plate has a graduated scale reaching from the
touch hole to the bridge, that is to say, along all the length of the ring of powder.
This graduated scale may be marked in metres or seconds, or both if desired.
The safety tube is arranged as in the percussion fuse with the exception that the
tongues in front of the ferrule being superfluous are dispensed with. The leaden
weight is also solid instead of being bored.
Before the discharge of each projectile the fuse must be adjusted, that is to say,
that a given point of the scale, determined by the time the shell must travel before
exploding, is set opposite the fixed pointer or index. On the shock of the discharge,
the capsule by its inertia bends back the retaining tongues into their straight position.
The detonator flies against the percussion or striker pin and ignites. This flame,
increased by the priming of powder, passes by the touch holes into the fire groove,
and from there is transferred to the part where the powder ring commences, which
Burns away till opposite the index, at which point the channel is placed conveying the
flame to the charge inside the shell.
The double acting fuse is the result of the combination of the two new systems of
percussion and time fuses, and its mode of working is analogous to that of the two
fuses described above. This construction allows of the certainty of its charge
exploding by one method or the other. for even if the end of the time fuse should
not come in contact with the charge the explosion will take place by the action of the
percussion fuse.
This new arrangement of fuses can be placed either at the front or breech of a shell.
In conclusion I do not limit myself to the exact details or materials described, as
these may be varied without departing from my invention.
Dated this 1st day of November 1880
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or appertaining to Percussion and Time Fuses for
Firing Explosives.
I, ARNOLD WALTER, of 59. Rue de Provence, Paris, in the Republic of France,
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:-
This invention relates to percussion and time fuses for igniting the explosive charges
in projectiles fired from mortars, and mountain, field, siege, naval and other guns; its
objects being to simplify the construction and lessen the cost of manufacture, to
render the action more certain, to ensure safety during manipulation and transport, to
hermetically enclose the parts liable to absorb moisture or become too dry, to avoid
interfering with that pointed shape of the projectile which is necessary to ensure
accuracy of flight, to adapt the fuse for being carried either at the fore or at the rear
part of the projectile, and, by economizing space, to enable the projectile to carry a
more formidable charge.

page_text: One form of fuse constructed according to this invention is double-acting; that is,
it consists in the combination of a percussion fuse with a time fuse: The priming of
the time fuse leads to a channel or groove into which powder has been rammed, more
or less of such powder being consumed before the flame reaches the point at which
the explosive charge contained in the shell is ignited.
The igniting device hitherto in use consists of a cylindrical body capable' of sliding
longitudinally and formed with a pointed extremity; the latter serving as a firing pin
to strike the fulminate and explode it. Such body is usually retained in its normal
position by a steel spring, a lead washer, a copper pin, or a light metal support, so
arranged as to prevent longitudinal displacement until after the projectile has struck
the object at which the gun was pointing. When the flight of the projectile is
suddenly arrested, the inertia of the cylindrical body overcomes the resistance of the
spring, washer, pin, or support, whereupon the pointed extremity of the cylindrical
body strikes the fulminate; the charge or the fuse being thereby ignited. A device
so constructed presents serious drawbacks. For instance, the means described above
for retaining the cylindrical body in its normal position do not effectually guard
against displacement whilst the projectile is being handled or subjected to the shocks
incidental to transport.
In the accompanying drawings,
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Fig. 1 represents in horizontal section a percussion fuse constructed according to
this invention and adapted for firing heavy charges; the plug and the firing pin being
in one piece.
Fig. 2 is a corresponding plan.
Fig. 3 is a horizontal section of a percussion fuse in which the plug at the point of
the fuse is dispensed with; the firing pin being inserted from the rear instead of the
front end of the fuse.
!I
Fig. 4 is a horizontal section of a percussion fuse adapted for firing light charges;
the plug and the firing pin being in one piece.
Fig. 5 is a corresponding plan.
Fig. 6 is a horizontal section shewing a percussion fuse, adapted for igniting light
charges, in which the plug at the point of the fuse is dispensed with.
Fig. 7. is a horizontal section of a time fuse.
Fig. 7 is a vertical section through the screw-threaded part of the fuse on the
line 7, 7*.
Fig. 8 is a plan corresponding with Fig. 7.
Fig. 9 is a plan of a combined percussion and time (that is, a double-acting) fuse
designed for igniting light charges and adapted for use with projectiles fired from
mortars;
Fig. 10 being a corresponding horizontal section.
Fig. 10 is an elevation shewing the rear side of the regulator.
31
Fig. 11 is a plan of a double-acting fuse for heavily-charged projectiles fired from
mountain, field, siege, or naval guns;
Fig. 12 being a corresponding horizontal section.
Fig. 13 is a plan of a similar fuse for lightly-charged projectiles;
Fig. 14 being a corresponding horizontal section.
i
In the percussion fuse illustrated in Figs. 1 and 2, the upper part a of the hollow
body of the fuse in shape resembles a truncated cone, and carries at its extremity a
plug b, which forms the point of the projectile. The lower part a' of the body is
screw-threaded, and is screwed into the end of the projectile. The part a has two
flats with which the key used to screw the fuse into the projectile engages. The
firing pin b' is formed on the plug b. The notch b² is for the reception of the screw-
driver by means of which the plug is screwed into the fuse. The safety tube c is
preferably made of drawn copper, and has several tongues c' punched out and bent in
towards its axis. The sides of each tongue should be equal; each side being longer
than the part where the tongue is bent over. These tongues serve to retain in its
normal position a brass capsule d containing a perforated lead cylinder & in which is
fixed the detonator d'. The capsule d is closed by the perforated plate ³. A

page_text: perforated body d' of compressed gunpowder is placed in the perforated cylinder d²
below the detonator d' in order to ensure that the flash from the detonator is com-
municated through the hole to the explosive charge contained in the projectile.
The hole a is closed by a thin copper disc a', which is pressed into a circular groove
or channel in the part a'.
When the flight of the projectile is suddenly arrested, the weighted capsule d, by
reason of its inertia, travels on, forcing back the tongues c' into the spaces c*, until
the detonator d' strikes against the firing pin . The fulminate in the detonator is
thereupon exploded, the compressed body d' of powder fired, and the disc a'
blown out of the hole ; the explosive charge in the projectile being ignited by the
flash.
In the construction shewn in Fig. 3, the plug e at the rear end of the fuse is
substituted for the plug at the fore end. The firing pin b' is screwed into the rear
side of the head of the fuse by a forked key, and is prevented from coming unscrewed
by the safety tube c. The safety tube c and the weighted capsule are kept in
position in the body of the fuse by the plug e. The hole is in this instance formed
in the plug e, and stopped by a disc a' as described with reference to Figs. 1 and 2.
In Figs. 4 and 5, the weighted capsule d is held between two sets of tongues
projecting from the safety tube c. Each tongue e in the front set is bent inwards to
an angle of about 45°; each tongue in the back set being bent inwards to an
angle of 90°. When the projectile is moved by the discharge of the gun, the
tongues care forced back by the weighted capsule d. the inertia of which is
subsequently overcome by contact with the paper collar f. When. the flight of the
projectile is suddenly arrested, the weighted capsule d, by reason of its inertia,
travels on, forcing back the tongue c² until the detonator d' strikes the firing pin b';
the explosive charge being thereupon ignited,as previously explained with reference to
Figs: and 2.
In Fig. 6. the plug e is substituted for the plug b. The firing pin b' is screwed
into the rear side of the head of the fuse. The safety tube c, with the weighted
capsule d. is located between the firing pin b' and the plug c. This variation in
construction does not affect the action of the parts.
The time fuse represented in Figs. 7 and 8 comprises a body A, the upper part a of
which is turned cylindrical to receive the regulator G the latter being held in
position by the nut H. The lower part a' of the body of the fuse is screwed into
the projectile. The capsule d is weighted with a solid lead cylinder d", and is inserted
at the front end of the body of the fuse, which is covered by the cap J. The nut H
is formed with flats a to enable it to be screwed up by a key: the cap J being
provided with a nick for the reception of a screw-driver. Surrounding the firing
pin b is a ring k of compressed gunpowder, the purpose of which is to render the
ignition of the fuse more certain. Radial passages / lead from the chamber containing
the detonator to an annular groove l'cut in the body of the fuse. The annular
groove communicates with a chamber m in the regulator G, which chamber contains
a body of gunpowder n, perforated as shewn. The chamber m is closed externally by
a copper disc m.. A groove o is cut on the rear side of the regulator. This groove
communicates with the chamber m, and extends nearly the whole of the way round
the regulator. It is filled with compressed gunpowder. The ring of powder is kept
dry by a felt washer p placed between the regulator and the body of the fuse. The
part a' is hollow and filled with loose gunpowder. It is closed by a copper disc a.
The groove o communicates through a hole in the washer p and byway of the passage q
with the chamber in the part a'.
On the discharge of the gun, before the inertia of the weighted capsule is over-
come, the firing pin be strikes the detonator; the fulminate and the ring of powder
being thus ignited. The flash enters the groove by way of the passages 1 and
ignites the powder contained in the chamber m. This has the effect of displacing the
disc m'. When the flame reaches the passage q, the loose gunpowder in the part a'
is fired and the disc a displaced the explosive charge contained in the projectile
being thereupon ignited. When the regulator G is in its normal position, as

page_text: illustrated, the chamber m lies exactly over the passage g. the location of which is
indicated by the nick q'. If the fuse be desired to fire the explosive charge at any
given fime say 15 seconds after leaving the gun, the nut is slightly unscrewed
and the regulator G turned until the corresponding number comes over the nick q
The nut is then tightened. The effect of so turning the regulator is that before
the passage q can be reached by the flame from the chamber m, a determined quantity
of the compressed powder in the groove o must be consumed. The timing of the
fuse is thus under complete control.
$
The arrow q marks the position of the solid metal q* (Fig. 10º) left between the
end and the commencement of the groove o. Before the fuse is packed for transport.
the arrow should be brought into line with the nick q'. This brings solid metal
over the passage q.and thus effectuallycuts off communication between the compressed
powder and the loose powder in the fuse. Should, therefore, the detonator be
accidentally fired, the flame would not reach the explosive charge.
The double-acting fuse illustrated in Figs. 9 and 10 contains a double firing pin b' b².
The pin b', on the discharge of the gun, strikes the detonator carried by the weighted
capsule d. This ignites the compressed powder by the burning of which the timing
of the fuse is effected. By the use of two regulators G and G₁, a greater length of
time may clapse after the firing of the gun before the projectile explodes. "If the
hole in the powder-chamber m' be left immediately over the hole m² in the
powder-chamber m', the latter being over the passage q. as shewn in the drawings.
the flame from the chamber mm is communicated directly to the chamber m and
thence to the loose powder in the passage q³: the explosive charge being then
ignited. If, however, the regulator G' be turned until the end of the groove o' is
over the hole m². the projectile will travel for 15 seconds-that is, for the period
Occupied by the burning of the compressed powder in the groove o'-before èxploding.
If the relative positions of the two regulators G and G' be maintained and the end of
the groove o brought over the passage q³, the projectile will travel for 35 seconds
before exploding. The washer q' may be prevented from turning independently in
any suitable way, such as by a projection or projections left thereon and which
engages or engage in a recess or recesses in the body of the fuse. The pointer qº
serves to enable the regulator G¹ to be properly set according to the scale. It is
obvious that by turning the regulator or regulators to a less extent, the fuse may be
set for any time between 1 second and 35 seconds. The cap J' takes the places of
the cap J and the nut H shewn in Figs. 7 and 8. If the flight of the projectile be
arrested before the time fuse has fired the explosive charge. then the detonator in the
weighted capsule & strikes against the firing pin b the explosive charge being,
under such circumstances, fired by the percussion fuse.
If it be desired to employ the double-acting fuse as a single-acting percussion fuse.
the regulator G is turned until the space q* between the ends of the grooves o'
the position of which is indicated by the arrow q, is brought over the hole 'm²; the
communication through the time fuse being thus interrupted. If preferred. the
regulator G may be turned instead of or in addition to the regulator G: Under
such circumstances, when the time fuse is ignited on the firing of the gun, the
compressed powder only burns to the point where the communication through the
fuse is cut off the time fuse being thus rendered inoperative so far as regards
the ignition of the explosive charge.
In Figs. 11 and 12, one regulator only is shewn.
the pointer q being used instead. The weighted
tongues c'.
The notch q' is dispensed with:
capsule d is held by one set of
In Figs. 13 and 14. the weighted capsule d is held between two sets of tongues c¹
and c².
The regulators G and G¹ may be marked with scales to shew the distance to be
travelled by the projectile, instead of with scales to shew the time which will clapse
after the firing of the gun, before the explosive charge is ignited.
The great advantage of the double-acting fuse is that, should the time fuse fail to

page_text: ignite the explosive charge, the ignition is effected by the percussion fuse directly the
flight of the projectile is arrested.
The fuses shewn in the accompanying drawings may be placed either in the fore
part or in the rear part of the projectile, and may be used with projectiles travelling
at any velocity. The tongues c', c, or are varied in number or in size or the
degree of their inclination is changed in order to produce the desired resistance to the
movement of the weighted capsule.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I claim :-
1. The improved percussion fuse for firing the explosive, charge contained in a
projectile, the same being constructed and operating substantially as described with
reference to the accompanying drawings.
2. The improved time fuse for firing the explosive charge contained in a projectile,
the same being constructed and operating substantially as described with reference to
the accompanying drawings.
3. A double-acting fuse for firing the explosive charge contained in a projectile
during, or at the termination. of, the flight of the projectile, the same being con-
structed and operating substantially as described with reference to the accompanying
drawings.
4. A fuse of specially small size and so constructed and arranged as to constitute
the point and complete the elongated form of the projectile, substantially as herein
described, and whereby the efficiency of the latter is increased.
5. In a fuse for firing the explosive charge contained in a projectile, a safety tube c
having tongues c', or c² and c", for retaining in its normal position the weighted
capsule of the igniting device, substantially as herein described.
6. In a fuse for firing the explosive charge contained in a projectile, the firing
pin bor b², or the double firing pin bb, arranged and operating substantially as
herein described.
7. In a time fuse of the kind herein referred to, the use of a washer or washers of
felt or similar material for keeping the ring. or rings of powder from absorbing
moisture or becoming too dry, and thus ensuring regularity in the burning of the
fuse, substantially as herein described.
8. The adjustable time fuse for use with a projectile fired from a mortar.
substantially as herein described; the same comprising two regulators arranged
concentrically one before the other, each regulator containing a ring of compressed
powder, one ring or both rings of powder being partially or wholly consumed
according to the length of time required to elapse between the firing of the mortar
and the explosion of the projectile.
9. In a double-acting fuse for firing the explosive charge contained in a projectile,
the employment of a passage, such as q. formed in the body of the fuse, substantially
as herein described, and serving to establish communication between the time fuse
and the explosive charge.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Agent for the Applicant.