Improvements in Electric Firing Mechanism for Breech Loading Guns.
Year: 1888

page_text: Date of Application, 20th Nov., 1888
Complete Specification Left, 19th Aug., 1889-Accepted, 5th Oct.,
1889
PROVISIONAL SPECIFICATION.
Improvements in Electric Firing Mechanism for Breech
Loading Guns.
I, THORSTEN NORDENFELT of 53 Parliament Street, Westminster, Civil Engineer,
do hereby declare the nature of this invention to be as follows:-
In the Specifications of former Patents applied for by me Nos. 17351 of 1887,
2604 of 1888 and 5743 of 1888 I described breech loading mechanism in which the
breech block was formed with a divided screw thread so that it could be released by
a partial turn and be then drawn back into a ring and be carried in this ring to one
side of the gun-the ring then turning on an axis parallel with the bore.
I now form such guns with electric firing mechanism in the following manner :-
The breech block is formed with a cavity extending into it centrally from its rear
end. Into this cavity an electric battery is inserted which with insulating material
surrounding it just fits the cavity-the rear end of the cavity is closed by a screw
plug. From the front end of the cavity a contact rod extends and protrudes slightly
from the front face of the block. Preferably the rod is pressed forwards by a spring
which also serves as a conductor between the rod and a metal plate at the front end
of the casing of the battery which is in electrical connection with one pole of the
battery. In this way one pole of the battery is brought into contact with the
ordinary insulated central stem of the electric fuze at the centre of the base of
the cartridge when the gun is loaded. The other pole of the battery is in connection
with a metallic ring which surrounds the exterior of the rear end of the battery
casing and which is insulated from the metal disc at the front end of the casing.
A contact rod passes radially through the breech block from a point opposite to
this ring and is normally held away from the ring by a spring. The ring into which
the rear end of the breech block extends also has passing radially through it a contact
rod the inner end of which comes opposite to the outer end of the contact rod in the
breech block when the breech block is closing the rear end of the gun. The rod
carried by the ring is normally held back by a spring from coming into contact with
the rod carried by the block it is also in electrical contact with the ring and so with
the metal of the gun.
When the gun is loaded it can be fired by pressing inwards the rod carried by the
ring and causing it to press inwards the rod carried by the block and bring the inner
end of this rod into contact with the ring which surrounds the rear end of the battery.
A circuit will then be completed from one pole of the battery to the other through
the fuse in the cartridge and the cartridge will be fired.
The pressing inwards of the contact rod carried by the ring may be effected by a
lever acted on by a cord or may be effected in other convenient way.
The breech blocks of breech loading guns of other construction than those
described in my former applications for Patents may also be formed with a cavity
within them to receive the electric battery used for electric ignition of the
cartridges.
.
Dated this 19th day of November 1888.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Firing Mechanism for Breech
Loading Guns.
I, THORSTEN NORDENFELT, of 53 Parliament Street, 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:-
In the Specifications of former Patents applied for by me Nos. 17351 of 1887,
2604 of 1888 and 5743 of 1888 1 described breech loading mechanism in which the
breech block was formed with a divided screw thread so that it could be released by
a partial turn and be then drawn back into a ring and be carried in this ring to
one side of the gun-the ring then turning on an axis parallel with the bore.
I now form such guns with electric firing mechanism in the following manner :-
The breech block is formed with a cavity extending into it centrally from its rear
end. Into this cavity an electric battery is inserted which with insulating material
surrounding it just fits the cavity-the rear end of the cavity is closed by a screw
plug. From the front end of the cavity a contact rod extends and protrudes slightly
from the front face of the block. Preferably the rod is pressed forwards by a
spring which also serves as a conductor between the rod and a metal disc at the front
end of the casing of the battery which either permanently or preferably only at the
instant of firing is placed in electrical connection with one pole of the battery. In
this way one pole of the battery is brought into contact with the ordinary insulated
central stem of the electric fuze at the centre of the base of the cartridge when the
gun is loaded. The other pole of the battery is in connection with a metallic ring at
the exterior of the rear end of the battery casing and which is insulated from the
metal disc at the front end of the casing.
A contact rod passes radially through the breech block and is normally held away
from the ring forming the battery terminal by a spring. The ring into which the
rear end of the breech block extends also has passing radially through it a contact
rod the inner end of which comes opposite to the outer end of the contact rod in the
breech block when the breech block is closing the rear end of the gun. The rod carried
by the ring is normally held back by a spring from coming into contact with the
rod carried by the block it is also in electrical contact with the ring and so with the
metal of the gun.
When the gun is loaded it can be fired by pressing inwards the rod carried by the
ring and causing it to press inwards the rod carried by the block and bring the inner
end of this rod into contact with the ring at the rear end of the battery which forms
the battery terminal. A circuit will then be completed from one pole of the battery
to the other through the fuse in the cartridge and the cartridge will be fired.
The pressing inwards of the contact rod carried by the ring may be effected by a
lever acted on by a cord or may be effected in other convenient way.
If as is preferred the disc at the front end of the casing of the battery is not
permanently connected electrically with the battery then the contact rod as it moves
forward is made to establish this connection by thrusting forward a needle which is
insulated from the contact rod but permanently connected with the battery pole.
The breech blocks of breech loading guns of other construction than those described
in my former applications for Patents may also be formed with a cavity within them
to receive the electric battery used for electric ignition of the cartridges.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.

page_text: a is the breech block which is adapted to the breech of the gun by a divided screw
thread on its exterior; but this as it forms no part of the present invention is not
represented in the drawings.
bis the ring in which the breech block is carried when it is withdrawn ; this ring
can turn for part of a revolution around the stud axis 61 which is fixed into the
breech end of the gun. The ring 6 carries the contact c which to fire the gun is
thrust in wards by pulling a lanyard or in other convenient way. In the breech block
there is a central cylindrical cavity and in this cavity the battery cell is contained.
The case consists of an ebonite cylinder d closed by a cover d' of the same material
and enveloped in soft india rubber d' and over this there is a jacket of vulcanised
fibre to prevent chaffing of the india rubber when the casing is thrust into the
cavity in the breech block. A silver tube e extends from end to end of the casing.
The casing contains preferably silver and zinc plates together with chloride of
silver and chloride of ammonium in solution; or in place of the latter caustic potash
may be employed. The silver plates are covered with precipitated chloride of silver
which is attached to the plate by partial fusion and the plate is then enveloped in a
bag of linen or parchment paper. Each silver plate is coated with chloride or both its
faces except that at the centre of the cell there are two silver plates one on either
side of the tube e and these are coated on one side only. Figure 3 is an end elevation
of the battery cell and Figure 4 is a section. The silver plates are marked ff and
the zincs which lie on either side of them are marked gg. Each silver plate has a
tail which projects through a slit in the cover d'; it also passes through a slit in
a silver plate which lies against the outer face of the cover and it is attached to this
plate by solder.
The zinc plates 9 are also provided with projections or tails gland by these they
are attached to the bar i. The parts g, g¹ and are shown in perspective by the
Figure 6. The tails are received into notches in the cover of the casing d.
Between the zincs and the coated silver plates several thicknesses of blotting paper
are placed and also in each case a thin sheet of finely perforated celluloid. When the
plates are all in place the joints around the cover d are made-tight by an insulating
cement. When required for use the battery cell is filled through a hole in the cover
with a saturated solution of salammoniac and the hole is then plugged.
In place of salammoniac a solution of caustic potash may be used as already
stated.
The cell it will be seen contains little or no free liquid but the liquid is held in the
pores of the absorbent material.
Over the silver plate ha covering k of vulcanised fibre is placed and this forms a
flat surface against which the ring / rests. This ring is shown separately by the
Figures 7. This ring also rests upon the bar i and so is always in electrical con-
nection with the zincs of the battery cell.
The ring I prefer to provide with a moveable part or flap jointed to it and it is
with this that the contact pin m in the breech block makes contact in order to fire
the gun. The contact pin m is enclosed in a casing n of vulcanised fibre by which it
is insulated and a spring presses it outwards. Behind the ring and the flap is an
insulating cup of vulcanised fibre o shown separately by the Figures 8. In this cap
there is an opening for the contact pin m to pass. The cavity in the breech block is
closed in rear by a screw plug p and a packing of india rubber and a steel disc is
interposed between the plug and the insulating cap o.
At the fore part of the breech block there is a pin q pressed forward by a spring g¹
and when the breech is closed this pin makes contact with the electric fuse of the
cartridge. The spring g' abuts on the disc r and this together with the spring and
pin is insulated by the case of vulcanised fibre in which the parts are contained.
A steel needle t passes through the silver tube e and when it comes into contact
with the discrit establishes electric connection between the pin q and the silver plates
of the battery cell. The needle t however is pressed rearwards by the spring t¹
against the insulating cap of vulcanised fibre inserted into the flap . When the
contact rod m is moved inwards by the outer contact rod c being made to abut upon

page_text: it it displaces the flap l' overcoming the spring t¹ and the needle t by its fore end
makes contact with the disc r. The battery current then passes from the silver plates
to the tube e thence to the needle t the disc r and the pin q. As the pin q is in
contact with the electric fuse of the cartridge the current traverses the fuse and so
passes to the metal of the gun. The current thus reaches the ring b from whence it
passes by the contact pins cm (which at this time are thrust inwards) to the flap
and bar i and so to the zincs g of the battery cell. The circuit thus being complete
the gun is fired. If desired the needle t may be prolonged to make direct contact
with the electric fuse in place of providing intermediate parts but the arrangement
shewn is preferable.
It is not essential to my invention that the battery cell should consist of the
elements above enumerated-other elements may be substituted but I prefer the
arrangement described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The combination with the breech block of a breech loading gun of a battery cell
contained within the block and mechanism for closing the circuit of this cell through
the electric fuse of the cartridge substantially as described.
2. A cannon provided with a block a for closing the breech; such block entering
the barrel at its breech end and being locked therein by a divided screw thread ; and
Buch block also being hollow and containing a firing battery which when its circuit is
closed ignites the charge and fires the gun substantially as described.
3. Electric firing mechanism substantially as described and represented by the
annexed drawings.
Dalth: 10th dow of Amon 1000