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38 has a base 39 of plastic or other insulating material. lan.t cup; a support screen between said spacer and said
An electrical heating element 40 is embedded in the primer delay tube; and a delay train comprised of a first fire
powder 41, with one end 42 passing through the insulat- layer of powder, a succession of layers of slow burning
ing base 39 to the exterior for contact with an electrical powder, and an afterfire layer of powder, each of said
firing means, and the other end 43 grounded to the case 5 layers having an axial length less than its diameter, and
44 of the cartridge 37. Thus, when the cartridge 37 is each having been consolidated under a pressure of be-
placed in a firing tube with the element end 42 against tween 20,000 and 50,000 pounds per square inch.
an insulated terminal electrically communicating through 2. A delayed firing cartridge which includes: an elon-
a switch (not shown) with a source of electrical power, gated -tubular imperforate side walled case having a firing
and the other terminal of said source is in electrical 10 end with a relatively heavy wall and a discharge end with
communication with element end 43 by ground connec- a relatively large opening; a primer housed in a primer
tion, firing can be accomplished by closing the switch. chamber in said heavy wall at said firing end, said primer
Cartridge 37 has cylindrical extension 45 instead of chamber being in communkation with the interior of said
flanges at the discharge end, and a self-contained piston case through a restricted primer discharge opening; a
46 to which the propellant 47 delivers its work output. 15 propellant charge housed in a propellant cup located in
The exterior of the cylindrical extension 45 may be said discharge end, said propellant cup opening toward
threaded to provide convenient attachment to the device the discharge end and having a restricted propellant fir-
which its piston 46 is intended to actuate. ing opening communicating with the interior of said case
The cartridge 50 illustrated in Figure 4 is radically toward said firing end; a closure cover over the discharge
different from the two embodiments illustrated in Figures 20 opening of said cup; a cylindrical spacer in the firing end
1 to 3, in that the time delay train is designed to burn of said case enclosing an empty primer discharge space
radially instead of axially. The case 51 is relatively into which said primer is adapted to discharge through
short in axial length and large in diameter. Its base 52 said primer discharge opening, the walls of said spacer
is solid and contains no primer recess or opening to the being provided with transverse openings to permit open
interior of the case 51. Indeed, this particular cartridge 25 communication between said primer discharge space and
contains no primer at all, although it will be understood the interior surface of said case; a delay train tube be-
that either the primer or primerless design may be used tween said spacer and said propellant cup, said tube being
with either radially or axially burning cartridges. of diminishing diameter toward said firing end to provide
An electrical firing lead 53 enters the cartridge 50 an annular space between the exterior of said delay tube
through its discharge end by way of an axial plug 54 30 and the interior wall of said case near said firing end; a
of plastic or other insulating material, which projects delay train within said delay tube, said delay train being
from a hole 55 in the center of the closure disc 56. comprised of series of a first fire layer of readily igniting
The electrical lead 53 passes through the interior of material, at least one layer of slow burning material, and
plug 54, emerging at 57. It is coiled around plug 54 in an after fire layer of readily igniting material arranged in
contact with a cylindrical layer 58 of first fire powder, 35 a series from said spacer to said propellant cup; and a
and at its terminus 59 is grounded to a perforated metal support partition providing pervious separati1;n betwee1~
tube 60, which is axially disposed within the shell 5.l. and said primer discharge space and the first finng end ot
seats on a shoulder 61 on the inner end of the plug 54. said delay tube.
The interior of the tube 60 provides a pressure cushion- 3. A delayed firing cartridge which includes: an elon-
ing chamber for combustion gases. 40 gated tubular imperforate side walled case having a firing
Three successive cylindrical time delay layers, 62, 63, end and a discharge end; a primer housed in a primer
and 64, and a cylindrical afterfire layer 65 enclose the chamber at said firing end; wall means defining a barrier
first fire layer 58. This radially burning time delay train between said primer and the interior of said case, said
is enclosed in a perforated metal cylinder 68. The wall being provided with a restricted opening between
annular space remaining within the case 50 is filled with 45 said primer chamber and the interior of said case; a cy-
propellant 67. lindrical spacer in the firing end of said case enclosing
Electrical firing of the cartridge 50 takes place in the an empty primer discharge space into which said primer
same manner as in the case of cartridge 37 of Figure 3, is adapted to discharge through said primer discharge
except that an electrical lead 53 from the discharge end opening, the walls of said spacer being provided with
is used for supplying the firing current, and the first fire 50 transverse openings to permit open communication be-
powder is fired directly without the intermediate firing tween said primer discharge space and an annular space
of a primer. between the exterior of said spacer and the interior sur-
It will be obvious to those skilled in the art of explosive faces of said case; a partition means transversely disposed
cartridges that many variations of my invention can be in said casing and positioned against said spacer, said par-
designed without departing from its scope. I have set 55 tition means being provided with -a plurality of small
forth the specific embodiments above described as illus- openings to provide open ·communication between said
trations and not for purposes of limitation, the limits of primer discharge space and the remainder of said casing
my invention being solely those set forth in the following toward the discharge end thereof; a delay train tube close-
claims. ly received in· said casing and positioned at one end
I claim: 60 against said partition means; a delay train within said
1. A delayed firing cartridge which includes: an elon- delay tube, said delay train being comprised primarily
gated tubular imperforate side walled case having a firing of slow burning material extending from said partition
end with a relatively heavy wall and an exterior recess, means at the firing end of said delay tube to the discharge
and a discharge end with a relatively large opening; a end thereof; a propellant charge housed in the discharge
closure disc closing said discharge end; a primer mounted 65 end of said casing; and propellant wall means transversely
in said recess in the exterior of said firing end and com- disposed in said casing between said delay train and said
municating with the interior of said case through an propellant charge, said propellant wall means being pro-
opening in said firing end; a cylindrical spacer disposed vided with a restricted opening for communication be-
coaxially within said case and enclosing an empty cham- tween said delay train and said propellant charge.
ber adjacent said firing end; a propellant cup in the dis- 70 4. A delayed firing cartridge which includes: an elon-
charge end of said case, said propellant cup having one gated tubular imperforate side walled case having a firing
end opening to said closure disc and having a relatively end and a discharge end; a primer housed in a primer
small opening toward the firing end; a propellant charge chamber at s-aid firing end; wall means defining a barrier
in said propellant cup; a delay tube for containing a time between said primer and the interior of said case,. said
delay train extending between said spacer and said propel- 75 wall peing provided with a restricted opening between