Improvements in Electric Fuses for Torpedoes and Explosive Projectiles.
Year: 1889

page_text: Date of Application, 10th July, 1889
Complete Specification Left, 10th Apr., 1890-Accepted, 10th Oct., 1890
"
PROVISIONAL SPECIFICATION.
Improvements in Electric Fuses for Torpedoes and Explosive
Projectiles.
I CORNELIUS EDWARD KELWAY of 71, Shardeloes Road, New Cross, London, S.E.
in the County of Kent, Electrical Engineer do hereby declare the nature of this
invention to be as follows :-
This invention relates to electric fuzes for torpedoes and explosive projectiles, in
which electricity electric or magneto-electric apparatus are employed for the ignition of
the bursting charge, and has for its object novel modes of accomplishing the same.
The chief novelty in this invention consists of the method of closing the electric
circuit by means of the power possessed by salt water for conducting electricity, so
that on the shell or torpedo entering or striking salt water a current of electricity
shall pass between the exposed ends of insulated wires connected with the poles of an
electric battery or other electric current producing apparatus and directly or indirectly
fire the bursting charge instantaneously or after any desired interval of time. This
fuse may he used with "high" explosives, as well as with those ordinarily used and it
may be inserted in the rear, head, or other part of the shell or torpedo.
" is
For the purpose of putting my invention in operation I sometimes employ a small
battery placed in circuit with a telegraphic "relay" of convenient shape and size with
insulated wires terminating at the rear or base of the fuze with their exposed ends
either flush with the fuze casing or in circular recesses or counter-sinks or in grooves
increasing in a direction contrary to that of the projectile's rotation, the object of the
latter being to facilitate the admission of water to the exposed ends. The ** relay"
an apparatus capable of being actuated by a feeble current which by closing a circuit
causes a stronger current to act. For the purposes of this invention the "relay" may
bring into action the current from a second battery or other source of electricity which
passing through a suitably arranged platinum "bridge" or fuze or detonator explodes
the charge. Or by a proper arrangement of wires the movement of the "relay
armature may complete a metallic circuit in connection with the one battery or other
source of electricity and the detonator and so economize space.
"
To guard against accidental completion of the circuit before the gun is fired a circuit
breaker preferably in the form of a weighted spiral or other spring is inserted which
is compressed by the shock of the gun's discharge and is then firmly held by a detent.
The above named apparatus may be enclosed in a metallic casing in one or more pirts
joined by screwed threads conforming to the shape of existing "service" fuses, or the
detonator may be placed in any part of the projectile.
"
When it is required to defer the time of brushing the shell the platinum "bridge
heated by the electric current or the spark created ignites a fuse composition or mealed
powder placed in a suitable channel or grove and communicating with a detonator and
the length of which channel or groove regulates the time of brushing calculated
from the time of immersion of the projectile in salt water.
This invention is particularly adapted for use with iny non-penetrating ship-sinking
projectile for which Provisional Protection No. 49 of the first of January 1889 has
been granted me.
It has also special value when used with shrapnel and segment shell as in ricochet
firing the shell can be made to burst in the air after the first graze on salt water and
so obviate the necessity for the use of time-fuzes, the necessary adjustment of which
for each distance seriously interferes with rapid firing.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Fuses for, Torpedoes and Explosive
Projectiles.
I, CORNELIUS EDWARD KELWAY, of 71 Shandeloes Road, New Cross, London, S.E.
in the County of Kent, Electrical Engineer, do hereby declare the nature of this inven-
tion 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 fuses for shells and torpedoes in which electricity or electro
magnetic apparatus is employed for the purpose of igniting the bursting charge con-
tained in such shells; and it has for its object novel methods of effecting such
explosion at the time desired.
My invention consists more especially in a novel method of completing the circuit
of the electric current for the purpose required by means of the electrical conducting
property possessed by salt water, so that when the shell or projectile to which the inven-
tion is applied strikes or is immersed in salt water, a circuit is completed through the
latter between the exposed ends of insulated wires connected with the poles of an
electric battery or other electric current producing apparatus of any suitable kind
contained in the shell or torpedo, and thus either directly or indirectly fires the
bursting charge either instantaneously or after any determined interval of time.
The improved fuse may be used with "high" explosives such as gun cotton or
dynamite, or with those ordinarily used such as gunpowder, and it may be either in
the head, the rear, or other part of the shell or torpedo.
In order to put my invention in operation I sometimes use a small electric.
battery placed in circuit with a "relay" device of the ordinary, well known kind,
the insulating wires connecting them not being continuous but being separated and
their ends or insulated plates or pole pieces connected with them, being exposed
at the rear or other exposed part of the fuse flush with the surface of the latter
or in recesses, countersinks, or grooves, preferably increasing in depth in a direction
contrary to that of the rotation of the projectile so as to facilitate the contact of
the water with the exposed insulated ends or plates. The relay device when the
circuit is completed operates an electro magnet capable of being actuated by a
very slight current of electricity and which when so actuated completes the circuit
from a much more powerful battery or other source of electricity also contained
in the shell or projectile. The current from this second battery passes through a
suitably arranged fine platinum wire or other device, or fuse or detonator, by
which the bursting charge of the shell or torpedo is exploded. Or by a suitable
arrangement of wires the movement of the "relay armature or equivalent device
may be made to complete the circuit or connection through the first battery, or
other source of electricity, and so explode the charge, and in this way a single
battery only is required, and space is economized.
"
In order to guard against the accidental completion of the electrical circuit before
the proper time I prefer to use a device by which the circuit is normally kept inter-
rupted. This I make preferably in the form of a weight which is forced forward by a
helical or other spring and in this position keeps the circuit broken. When the gun is
fired the spring is compressed by the inertia of the weight and the latter is then held
back in its new position by a detent or catch, and in this position the interrupted part
of the circuit is completed, and is ready for the entire circuit to be completed by the
action of the salt water upon the exposed ends of the insulated wires of the smaller
battery, and the consequent operation of the relay to complete the circuit of the larger
one as already described.
The apparatus may be enclosed in a metal case which may be made in two or more
parts screwed together, its external shape then perfectly corresponding with that of
the ordinary surface fuses in substitution for which it can be used. Or the improved
detonator described may be arranged in any convenient position in the shell.
In cases where it is required that the time of bursting of the shell should be
deferred for a greater or less time, the heat or spark produced by the completion of

page_text: the electric circuit may be made to ignite a slow burning fuse composition, or mealed
powder, placed in a suitable channel or groove communicating with a detonator by
which the bursting charge is fired, and the length of such channel or groove con-
taining the composition may be made adjustable so as to regulate the moment of
bursting calculated from the time of immersion of the projectile in salt water.
The improved apparatus described is of especial value when used with shrapnel.
and segment shell, as in "ricochet" firing the shell can be made to burst in the
air after the first graze on salt water, and thus obviate the necessity for the use
of time fuses, the necessary adjustment of which for each distance seriously
interferes with rapid firing.
My invention is also applicable to cases in which it is desired that a shell
shall strike a vessel but without penetrating the latter, dropping instead from
the side of the vessel after striking and exploding after it has fallen into the
water.
For this last described purpose I prefer to modify somewhat the arrangement
above described. I use instead of the moveable weight pressed forward by a
spring as described, a small centrifugal governor of any of the well-known kinds,
inside the fuse, the moveable arms of which governor are attached or connected
to a device by which, when the shell is rotating and causing a simultaneous
rotation of the balls or weights of the governor which rotate with it, a wedge
shaped piece which is arranged between an electro magnet in the fuse and the
armature which is to be attracted by it is withdrawn, and when by the contact with
salt water the circuit of the current from the smaller battery is completed and its
electro magnet operated, the armature of the latter can be attracted, and the circuit
of the larger battery completed and the charge exploded.
In the accompanying drawing which is in illustration of my invention, Figure 1 is
a longitudinal section through a fuse.
A is the battery cell of any suitable insulating material or materials, B is the
battery, and b and c the positive and negative poles continued as screwed plugs
through the insulated material forming the base of the cell which base is preferably
attached by means of the screwed thread as shown. d is a screw plug to admit
of the application of water or other liquid or ingredients when it is required to
sensitize or render the voltaic battery capable of action on the circuit being com-
pleted as hereinafter shewn. b and c are not in metallic connection with plate e.
C is a casing or cylinder of any suitable metal or other material closed at one
end by plate e, which latter holds insulated blocks, through which are passed the
screws f,in metallic connection with the pole pieces b and c. These screws f; ƒ³
also serve the purpose of connecting the battery to the plate e, which latter carries an
external thread to which is screwed the metallic cap or cover D.
E is an electro-magnetic "relay" apparatus, with the collar of its bobbin resting in
a recess in plate e, and held in position by two metallic straps or brackets attached to
it and to the cross bar g and having its circular iron core i extending beyond the
bobbin in half round" shape.
To the bobbin is fixed an insulated block k which supports, by means of the flat
spring the armature m carrying the contact piece n, which latter when an electric
current passes round the coils and core i, nakes contact with the insulated block o
affixed to the bobbin.
In this case the movement of the armature due to the current is at right angles
to the length of the core and preferably in a direction corresponding with that
of the rotation of the projectile. and p are recessed insulated blocks placed in
grooves deepening in a direction contrary to that of the projectile's rotation. To
the recessed metallic block p which is insulated from the casing or cylinder C,
an insulated wire is connected to screw f, and from f¹ an insulated wire is con-
tinued with the necessary. number of coils around the bobbin and core and is ter-
minated in metallic connection with the insulated metallic block p'. On the fuse being
immersed in salt water the electric circuit is completed viz. from p to f, through
battery, from through coil to pl, and, through water to p when the armature m

page_text: is actuated, bringing n and o into contact. From a second wire is connected
with the platinum
"bridge" F, thence to block k. From f¹ another insulated
wire is led to contact block o. On the electro magnet being actuated by the
current as previously described the movement of the armature m brings n and o
in contact, a complete metallic circuit is thereby effected through the battery, the
second pair of wires, armature and platinum bridge or fuse or detonator, and the
projectile is exploded.
G is a spindle whose fine pointed end of insulated material intervenes between the
armature m and the half-round part of core i before the projectile is fired, and is
normally held in this "safe" position by the spiral spring h resting between the
collar and the cross-bar g. The point of G may be flat or wedge shaped. His
a circular or other shaped weight pinned or otherwise secured to G after the
latter is placed in position, and is grooved as shewn. I, 11 are two springs, or
detents bolted to cross bar and pressing against H. On the discharge of the gun
the weighted spindle G is thrown backwards, its point is withdrawn from between m,
and i, and the armature is free to move by the action of the electric current
and H is beld firmly by the detents I, I'.
In Figure 2, q is a spring to regulate the tension on the armature m.
adjustable contact screw to limit the play of the armature.
r is an
In Figure 3, t, t, are governor balls, which when revolving draw back the bolt G.
The bolt G is then held back by detents or springs as in the modification shewn in
Figure 1.
I do not confine myself to the precise form and arrangement of the parts of my
improved fuse, which may be varied more or less as may be found advisable.
I am aware that explosive shells have been made containing electrical batteries by
means of which the explosive charge is fired at the required time, and I do not claim
generally the use of such electric battery, but having now described and ascertained
the nature of my said invention, and in what manner the same is to be performed,
I declare that what I claim is
1. In electric fuses for shells and projectiles, the arrangement of the exposed ends
of the insulating conducting wires by which the electric current passes by the agency
of which the charge is exploded, or of insulated plates or poles upon such wires, in
such manner that when the shell or projectile becomes wet with salt water such salt
water serves as a conductor to complete the electric circuit substantially as herein
described.
2. In such shells and projectiles the use of two electrical batteries or generators in
the fuse or shell, the circuit of the conducting wire from the first battery being com-
pleted by contact with or immersion in salt water, and thereby actuating a relay by
which the circuit of the second battery is completed and the explosive charge thereby
fired, substantially as herein described.
3. The combination with the electric battery or generator or batteries or generators
in the shell or fuse, of the safety device consisting of a weight which is pressed forward
by a spring in its normal position, but is pressed back and held by a detent or catch
when the gun is fired, thereby leaving the conducting wires in a condition to have the
electrical circuit through them completed and the charge exploded, when the shell
comes in contact with salt water, substantially as herein described.
4. As a substitute for the safety device claimed in the last claim, the centrifugal
governor, arranged and operating substantially as and for the purpose herein described.
5. In combination with the apparatus claimed in the previous claims, the channels
or grooves in the shells, containing a slow burning composition, for the purpose of
retarding the explosion, substantially as herein described.
EDWARDS & Co.,
35, Southampton Buildings, Chancery Lane, London,
Agents for the Applicant.
EDWARDS & Co.,
35, Southampton Buildings, Chancery Lane, London,
Agents for the Applicant.