IMPROVEMENTS IN ELECTRIC CARTRIDGES AND ELECTRIC PRIMERS THEREFOR
Year: 1885

page_text: therefor.
I SAMUEL RUSSELL, of N° 122 Montague Street, in the City of Brooklyn,
United States of America, Physician do hereby declare the nature of my
invention for "IMPROVEMENTS IN ELECTRIC CARTRIDGES AND ELECTRIC PRIMERS
THEREFOR to be as follows:-
33
This invention relates to cartridges to be discharged by electricity, by the
heating to incandescence of a conductor of high resistance in contact with the
powder.
In my complete Specification Nº 3505 of 1885 dated 22nd October 1884, I have
described an electric cartridge, the primer of which consists of a tubular sheath of
insulating material, with a metal conducting pin extending inside of it, and a
copper strip extending along its outside, and with an incandescing conductor
arranged at the front of the sheath and forming a connection between the front
ends of the said pin and strip. In the making of this primer difficulty has been
experienced in the attaching of this copper strip to the sheath. My present inven-
tion is intended to remedy this difficulty, and also to enable the primer to be made
complete in itself, in order that it may be sold separately from the cartridge shells,
as a distinct article of manufacture.
According to my present invention the cartridge shell is not necessarily charged.
It has a metallic base with a tubular neck turned inward at the centre of the base.
This neck should be very slightly conical. The electric primer consists of a central
pin, preferably of copper, a tubular sheath of insulating material inclosing this pin,
and a metallic tube inclosing the sheath. The incaudescing conductor is preferably
of slender platinum wire, its opposite ends soldered respectively to the front ends
of the copper pin and tube. The tube is preferably made slightly tapered or
conical, and the tubular sheath is forced into it with considerable pressure, making
a tight fit. The base or rear end of the tube is somewhat larger than the forward
portion, and is made a tight fit with the neck in the shell, so that considerable
pressure is necessary to force it into place. The primer is entered into the neck
from the rear end of the shell, and is pressed forward into the interior of the shell.
In cases where the joint thus made is insufficient to prevent escape of gas during
the firing of the cartridge, special provisions may be applied to form a gas check.
D
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page_text: One suitable method is to spin down to the base of the shell around the base of
the primer, thus compacting the metal at the base of the neck closely against and
around the primer.
In order to protect the platinum wire or other incandescing conductor from
injury during the handling of the primer, a recess is formed in the front end of the
primer in which recess this conductor is arranged. This recess is made by having
the outer tube longer than the insulating sheath, so that it extends beyond the
front end of the latter, and preferably also beyond the end of the central pin, thus
forming a recess in which the incandescing conductor may lie.
J. C. MEWBURN,
169, Fleet Street, London,
Agent.
COMPLETE SPECIFICATION.
Improvements in Electric Cartridges and Electric Primers
therefor.
I, SAMUEL RUSSELL, of No. 122 Montague Street, in the City of Brooklyn,
United States of America, Physician, do hereby declare the nature of my said
invention for "IMPROVEMENTS IN ELECTRIC CARTRIDGES AND ELECTRIC PRIMERS
THEREFOR," 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 cartridges to be discharged by electricity, by the
heating to incandescence of a conductor of high resistance in contact with the
powder.
In the Specification of my patent No. 3505 of 1885, dated 22nd October, 1884,
I have described an electric cartridge the primer of which consists of a tubular
sheath of insulating material, with a metal conducting pin extending inside of it,
and a copper strip extending along its outside, and with an incandescing conductor
arranged at the front of the sheath and forming a connection between the front
ends of said pin and strip. In the making of this primer difficulty has been
experienced in the attaching of this copper strip to the sheath. My present inven-
tion aims to remedy this difficulty, and also to enable the primer to be made
complete in itself, in order that it may be sold separately from the cartridge shell,
as a distinct article of manufacture.
According to my present invention the cartridge-shell is not necessarily changed
in any essential particular. It has a metallic base, with a tubular neck turned
inward at the center of the base. This neck should be very slightly conical. The

page_text: electric primer consists of a central pin, preferably of copper, a tubular sheath of
insulating material enclosing this pin, and a metallic tube enclosing the sheath,
with the incandescing conductor, which is preferably a slender platinum wire, the
opposite ends of which are soldered respectively to the front ends of the copper
pin and tube. The tube is preferably made slightly tapered or conical, and the
tubular sheath is forced into it with considerable pressure, making a tight fit.
The base or rear end of the tube is somewhat larger than the forward portion,
and is made a tight fit with the neck in the shell, so that considerable pressure is
necessary to force it into place. The primer is entered into the neck from the rear
of the shell, and is pressed forward into the interior of the shell. In cases where
the joint thus made is insufficient to prevent escape of gas during the firing of the
cartridge, special provisions may be applied to form a gas check. One suitable
method is to spin down the base of the shell around the base of the primer,
thus compacting the metal at the base of the neck closely against and around
the primer.
In order to protect the platinum wire or other incandescing conductor from
injury during the handling of the primer, a recess is formed in the front end of
the primer in which recess this conductor is arranged. This recess is made by
having the outer tube longer than the insulating sheath, so that it extends beyond
the front end of the latter, and preferably also beyond the end of the central pin,
thus forming a recess in which the incandescing conductor may lie.
The accompanying drawings show my improved cartridge on a magnified scale-
Figure 1 is a longitudinal mid-section of a rifle cartridge and its electric primer,
made according to my invention. Figure 2 is a transverse section thereof, cut on
the line 2-2 in Fig. 1. Fig. 3 is a longitudinal mid-section of the empty cartridge-
shell with the electric primer partly withdrawn. Fig. 4 is a longitudinal section
of the primer, separated, with end-views of its opposite ends. Fig. 5 is a longi-
tudinal section of an empty shell and primer showing a modification. And Fig.
is a longitudinal mid-section of a paper-shell cartridge for a shot-gun, fitted with
my electric primer.
Referring to the drawings, A. designates the shell of the cartridge, and B the
electric primer. The shell A is, as heretofore, of any usual construction, having a
tube of either metal, as in Figs. 1, 2 and 3, or of paper as in Fig. 6. In either
case its base a is of metal, and is forined with a central neck or short tube a¹
turned inward.
The primer B consists of the central metallic pin b, the insulating sheath c, the
outer metallic tube e, and the incandescing conductor d. This primer is preferably
made by first inserting the pin b in the sheath c, and then forcing the latter under
considerable pressure into the tube e, which is made by preference slightly tapering,
so that when the sheath is thus forced into place it fits very tightly. The platinum
wire d is then soldered at its opposite ends to the front ends of the pin and tube
respectively. The primer is then complete.
The tube e extends beyond the front end of the sheath c, thus forming a recess f
in which the platinum wire may lie. This slender wire is thus protected from
injury during the handling of the primer and during the loading of the cartridge.
When it is desired to unite the primer to the cartridge shell, the primer is
inserted into the shell from the rear, as denoted by Fig. 3, and pressed forward,
its enlarged base-portion e¹ fitting tightly within the neck a. The primer is thus
held firmly with its front end projecting into the interior of the shell. The shell
is then charged with powder and a bullet, as in Fig. 1, or with powder, wads and
shot, as in Fig. 6. The cartridge is then ready to be used and may be placed in
an electric gun to be fired. The electrical action is the same as described in my
said Specification No. 3505 of 1885.
The primer is not ordinarily injured by the firing of the cartridge, and may be
used many times in succession. In case, however, the primer becomes inoperative
from any cause, it may be forced out of the shell, and a new primer inserted. It
is intended that the primers and shells shall be sold separately, being made in

page_text: standard sizes to fit each other. Thus my improved electric primers constitute
a new article of manufacture and sale.
Fig. 5 shows a construction for affording a more perfect gas check. The primer
is pressed into the shell as already described, after which the base of the shell is
spun down at m against the base of the primer, as shown, thereby compressing the
primer and making a very close joint. The front end of the neck al is also made
slightly smaller than the portion of the primer which enters it, so that in forcing
in the primer it is expanded and a close and perfect fit is ensured. This figure
also shows how the pin b may be extended beyond the front end of the tube e, if
desired, for greater convenience in soldering the ends of the platinum wire d.
Having now particularly 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. An electric primer for cartridges consisting of a central metallic pin b, a
tubular insulating sheath c, an outer metallic tube e enclosing said sheath, and
a high-resistance conductor d at the front end, its opposite ends connected to said
pin and tube respectively, substantially as described.
2. A cartridge-shell A. having a metallic base a and neck a¹, in combination with
an electric primer B, fitting said neck, and capable of insertion in and removal
from the shell, as described.
3. The primer B having its tube e extended beyond the front of the insulating
sheath c, and forming thereby a recess at the front for the protection of the wire d,
as described.
O
Dated at New TOIN, ..., tins eighth day
In the presence of
ARTHUR C. FRASER,
Solicitor of Patents,
Temple Court, New York.
SAMUEL RUSSELL.
J. C. Mewburn,
169, Fleet Street, London,
Agent.