Year: 1887

page_text: Date of Application, 16th June, 1887
Complete Left. 16th Mar., 1888
Complete Accepted, 20th Apr., 1888
1, THORSTEN NORDENFELT, of 53 Parliament Street, in the City of Westminster,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object improvements in electrical apparatus to be used
with ordnance to fire the charge.
is
The charge is contained within a metal cartridge case and in the centre of the base
of this case a tube is inserted to receive the priming enclosed in an inner tube or
lining. There is a plug of vulcanite behind the priming and a fine wire is passed
through perforations in the plug. This wire when heated by the passage of the
electric current ignites the priming charge. Its ends are connected with the lining
of the priming tube and so it is in electric communication with the cartridge case and
also when the cartridge is in place with the entire mass of metal of which the gun
formed. The vulcanite plug is supported in rear by the head of a metallic button and
a loop of the fine wire which passes through the vulcanite plug rests against the
button making electrical contact therewith. The back of the vulcanite plug is
hollowed out to receive the head of the button so as to insure its electrical insulation.
A perforated metal disc is fitted into the base of the cartridge case to support the
button and the stem of the button passes through it. The stem is surrounded by a
collar of vulcanite, and a thin layer of vulcanite is interposed between the head of the
button and the metallic disc.
The breech block of the gun has a hard steel plug screwed into it, and this
upon
plug the metallic disc in the base of the cartridge case abuts when the cartridge case
is in the gun and the breech is closed. The steel plug is perforated, and it contains
within it a spring pin enclosed in a metal box surrounded with insulating material.
A hole is also bored in the breech block through which an insulated wire is led and it
terminates within the plug in electrical connection with the spring pin.
One end of this insulated wire is connected with one of the terminals of a firing
battery and the other terminal is coupled with the mass of metal composing the gun.
A contact making trigger is included in the circuit. When the trigger is pulled the

page_text: current passes from the battery to the spring pin thence to the metallic button in the
base of the cartridge case from this button through the thin firing wires to the metal
of the priming tube and thence to the cartridge case; to the gun and to the other
terminal of the battery. The wires within the cartridge then become leated and the
priming is thereby ignited.
When the gun is fired the pressure of the gases within the gun is exerted upon the
head of the metallic button in the base of the cartridge case and presses this back
upon the disc in the aperture in the base of the cartridge and only a thin layer of
vulcanite separates the two parts. The disc in the base of the cartridge case is in
turn supported by the steel plug in the face of the breech block so that nothing can
yield.
I also provide a testing battery and a galvanometer or indicator so arranged that
when the breech is closed an electric circuit is completed from the insulated wire in
the breech block to the metal of the gun by the course already traced. The current is
altogether insufficient to fire the charge, but it gives an indication on the galvanometer
or indicator if the firing wires are properly connected, and also it shows if there be
any short circuiting between the wire in the breech block and the gun.
The trigger is thus arranged; the lever which operates the breech block is provided
with a pin duly insulated and connected with the wire passing through the breech
block.
When the breech is properly closed this insulated pin comes close to another similar
pin which remains stationary upon the gun and from this pin an insulated wire passes
to the battery terminal.
When the trigger operates it bridges the space between the two pins and the
current passses; but this can only take place when the insulated pin on the lever has
arrived at its proper position for firing that is to say the breech must be securely
closed before the trigger contact can be made.

page_text: 1, THORSTEN NORDENFELT of 53 Parliament Street in the City of Westminster,
Civil 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 has for its object improvements in electrical apparatus to be used
with ordnance to fire the charge.
The charge is contained within a metal cartridge case and in the centre of the base
of this case a tube is inserted to receive the priming enclosed in an inner tube or
lining. There is a plug of vulcanite behind the priming and a fino wire is passed
through perforations in the plug. This wire when heated by the passage of the
electric current ignites the priming charge. Its ends are connected with the lining of
the priming tube and so it is in electric communication with the cartridge case and
also when the cartridge is in place with the entire mass of metal of which the gun is
formed. The vulcanite plug is supported in rear by the head of a metallic button and
a loop of the fine wire which passes through the vulcanite plug rests against the
button making electric contact therewith. The back of the vulcanite plug is hollowed
out to receive the head of the button so as to insure its electrical insulation. A
perforated metal disc is fitted into the base of the cartridge case to support the button
and the stem of the button passes through it. The stem is surrounded by a collar of
vulcanite, and a thin layer of insulating material is interposed between the head of the
button and the metallic disc.
The breech block of the gun has a hard steel plug screwed into it, and upon this
plug the metallic disc in the base of the cartridge case abuts when the cartridge case
is in the gun and the breech is closed. The steel plug is perforated, and it contains
within it a spring pin enclosed in a metal box surrounded with insulating material.
A hole is also bored in the breech block through which an insulated wire is led and
it terminates within the plug in electrical connection with the spring pin.
One end of this insulated wire is connected with one of the terminals of a firing
battery and the other terminal is coupled with the mass of metal composing the gun.
A contact making trigger is included in the circuit. When the trigger is pulled the
current passes from the battery to the spring pin thence to the metallic button in the
base of the cartridge case from this button through the thin firing wires to the metal
of the priming tube and thence to the cartridge case; to the gun and to the other
terminal of the battery. The wire within the fuse case then becomes heated and the
priming is thereby ignited.
When the gun is fired the pressure of the gases within the gun is exerted upon the
head of the metallic button in the base of the cartridge case and presses this back
upon the disc in the aperture in the base of the cartridge and only a thin layer of

page_text: electric fuses resembling mine have before been suggested but these have not been
wholly successful some of the parts from their construction or arrangement having
yielded when fired in large guns under heavy pressures I therefore do not make any
broad claim to electric fuses but I declare that what I claim is :-
1. The combination of the disc a¹ in the base of the fuse case and in contact with
the breech block, the button d and the thin layer of unyielding insulating material
between them substantially as described.
с
2. The combination of the priming tube a the plug 6 the wire c and the button d
substantially as described.
3. The hard plug in the breech block to support the base of the fuse case when
the gun is fired substantially as described.
4. The combination of the hollow plug f the spring pin g and insulated metal box /
substantially as described.
5. The testing arrangements with a cell or battery which is not sufficient to fire the
charge substantially as described.
6. My improvements in electrical apparatus to be used with ordnance to fire the
charge substantially as described.
ה ט
r A.
1000