Improvements in Electrical Firing Mechanism for Ordnance.
Year: 1887

page_text: Date of Application, 6th Aug., 1887
Complete Specification Left, 7th May, 1888
Complete Specification Accepted, 3rd Aug., 1888
PROVISIONAL SPECIFICATION.
Improvements in Electrical Firing Mechanism for Ordnance.
I, CHARLES AMBROSE McEvoy of the London Ordnance Works, Bear Lane,
Southwark in the County of Surrey, Engineer, do hereby declare the nature of this
invention to be as follows:-
In electrical firing mechanism as before made the firing of an electrical primer
carried at the centre of the rear end of a cartridge has been effected by conveying
an electric current to the centre of the rear end of the primer through an insulated
rod or firing pin which has been brought into contact with the primer immediately
that the breech block has been brought to its closed position and before the breech
block has been securely locked.
When this is the case there is danger of the cartridge being fired before the
breech block has been secured if in any way any imperfect electrical connection of
the firing pin with the battery is accidentally completed.
According to my invention I cause the firing pin to be held back by a spring so
that when the breech is closed its end shall not be in contact with the primer and
in order to bring it into contact with the primer whenever the battery circuit is
completed by the depression of a firing key I surround the stem of the firing pin
with an insulated coil of wire of comparatively high resistance one end of the stem
which is surrounded by the coil I form of iron so that when a current is passed from
the battery through the coil this end of the stem is drawn inwards towards the centre
of the coil and the firing pin is thereby brought into contact with the primer and so
soon as this takes place the primer being of comparatively low resistance the whole
current passes to it from the firing pin and the cartridge is fired. Any imperfect
completion of the battery circuit would be unable to overcome the resistance of the
coil by which the stem of the firing pin is surrounded and so would be unable to
bring the firing pin into contact with the primer.
In place of using a solenoid coil as above described for bringing the firing pin into
contact with the primer an electro magnet might be used.

page_text: I also use a solenoid coil or it might be an electro magnet for pulling the trigger
of the firing mechanism of ordnance in which the firing of the cartridge primer is
effected by percussion so that the firing may be effected by the depression of a finger
key which does not recoil with the gun. The trigger is usually carried by a pistol
handle I joint a rod to the back of the trigger and lead it through a coil of insulated
wire contained in a cavity in the handle and I form the forward end of the rod of
iron so that it may be drawn backwards whenever an electrical current is passed
through the coil. In this way the gun can either be fired by pulling the trigger by
hand in the usual way or electricity by the depression of a finger key as desired.
Dated this 6th day of August 1887.
CARPMAEL & Co., .
Agents for the Applicant.

page_text: Improvements in Electrical Firing Mechanism for Ordnance.
I, CHARLES AMBROSE MCEVOY, of the London Ordnance Works, Bear Lane, South-
wark, in the County of Surrey, 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 :-
In electrical firing mechanism as before made the firing of an electrical primer
carried at the centre of the rear end of a cartridge has been effected by conveying
an electric current to the centre of the rear end of the primer through an insulated
rod or firing pin which has been brought into contact with the primer immediately
that the breech block has been brought to its closed position and before the breech
block has been securely locked.
When this is the case there is danger of the cartridge being fired before the breech
block has been secured if in any way any imperfect electrical connection of the firing
pin with the battery is accidentally completed.
According to my invention I cause the firing pin to be held back by a spring so
that when the breech is closed its end shall not be in contact with the primer and in
order to bring it into contact with the primer whenever the battery circuit is com-
pleted by the depression of a firing key I surround the stem of the firing pin with
an insulated coil of wire of comparatively high resistance one end of the stem which
is surrounded by the coil 1 form of iron so that when a current is passed from the
battery through the coil this end of the stem is drawn inwards towards the centre of
the coil and the firing pin is thereby brought into contact with the primer and so
soon as this takes place the primer being of comparatively low resistance the whole
current passes to it from the firing pin and the cartridge is fired. Any imperfect
completion of the battery circuit would be unable to overcome the resistance of the
coil by which the stem of the firing pin is surrounded and so would be unable to bring
the firing pin into contact with the primer.
In place of using a solenoid coil as above described for bringing the firing pin into
contact with the primer an electro magnet might be used.
Figure 1 of the drawings annexed is a longitudinal section of one form of breech
block of a breech loading gun now commonly used fitted with a firing pin which is
held back as above described by a spring and drawn forward by a solenoid whenever
the battery circuit is completed to bring its forward end into contact with the primer
carried by the base of the cartridge with which the gun is loaded.
A is the rear end of a cartridge case carrying at its centre an electrical primer B-
C is a screw breech block-D is a metallic rod passing centrally through it-at the
rear end of this rod is, a head D'-this head and part of the length of the rod D is
of iron whilst the front portion of the rod is of non magnetic metal-E is a coil of
insulated wire surrounding part of the rod D-F is a metallic casing containing the
coil.
G is a spring interposed between the rear end of this casing and the head D¹ of
the rod D H is a casing of insulating material surrounding the metallic casing F
and a similar casing F1 by which the spring G and head D' are enclosed-1 is a screw
cover by which the casing H is retained within the cavity of the breech block. K is
an insulated wire carried through the cover I and brought into contact with the
metallic casing F-L is a disc of insulating material at the front end of the breech
block having a hole through its centre through which the front end of the rod D
passes.

page_text: One end E¹ of the wire coil E is secured to the metallic casing F the other end is
carried through the insulating casing H and coupled to a metallic spring or brush E
carried by the exterior of this casing and which comes into contact with the metal of
the breech block.
Normally the rod D is as above explained held back by the spring G-when the
battery circuit is completed the current passes from one pole through the wire K
metallic casing F wire coil E and through the breech block and gun to the other pole
of the battery. The current passing through the coil draws the rod D forwards and
brings its front end against the primer B the current then passes direct from the
metallic casing F through the spring G to the rod D and thence to the primer
A similar construction is shown in longitudinal section at Figure 2 the parts are
marked with the same letters of reference and their action is the same-the only
difference is that the insulated wire E in-place of being formed into a coil surrounding
the rod D is formed into coils surrounding two soft iron magnet cores and form
with them a horse shoe magnet which is secured to the front end of the insulating
casing H.
•
I also use a solenoid coil or it might be an electro magnet for pulling the trigger
of the firing mechanism of ordnance in which the firing of the cartridge primer is
effected by percussion so that the firing may be effected by the depression of a finger
key which does not recoil with the gun. The trigger is usually carried by a pistol
handle I joint a rod to the back of the trigger and lead it through a coil of insulated
wire contained in a cavity in the handle and I form the forward end of the rod of
iron so that it may be drawn backwards whenever an electrical current is passed
through the coil. In this way the gun can either be fired by pulling the trigger by
hand in the usual way or electricity by the depression of a finger key as desired.
Figure 3 shows the trigger of the firing mechanism of a gun and a solenoid coil for
pulling the trigger when the gun is to be fired.
A is the ordinary pistol handle B the trigger C an iron rod jointed to the back of
the trigger and passing into the centre of a cylindrical coil D of insulated wire con-
tained in a cavity in the pistol handle. The rear end of the wire coil is coupled to
the metallic casing E in which the coil is contained and an insulated wire is led from
this casing to a firing key and so to one pole of a battery the other end of the wire
coil is led through the front end of the casing E and secured to a metallic spring F
which is in contact with the metal body of the pistol handle from which an insulated
wire is led to the other pole of the battery.
With this arrangement the gun can either be fired by pulling the trigger in the
usual way or by completing an electric circuit through the coil D-the rod C is then
drawn backwards into the coil and pulls the trigger.
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. Carrying within the breech blocks of breech loading guns a coil of insulated
wire of comparatively high resistance and a conducting pin or rod for conveying an
electrical current to the primer of a cartridge which pin or rod is normally held back
by a spring so that its end does not come into contact with the primer but when an
electric current is passed through the coil is drawn forwards and its end brought into
contact with the primer and the current then passed direct through the pin to the
primer without passing through the coil.
2. The construction of the firing mechanism for breech loading guns substantially
in the manner herein before described with reference to Figure 3 of the drawings.
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