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tubular container 41 delay combustion of that part of FIGURE 1, the suppression of combustion' iii order to
the ignition charge 37 which surrounds the exterior of achieve a prolonged burning at a lower and flatter pres-
the container 41. sure peak is achieved by coating the pellets which are not
. ·. The first-stage ignition charge is supported within the in the immediate vicinity of the starting squib 16. In the
container 41 between transverse barriers 43 and 44; which 5 embodiment of FIGURE 2, the envelopment of the third-
may be referred to as upstream and downstream barriers stage pellets is accompLished by embedding them in a
relative to the direction of ignition burning. The barriers relatively less combustible solid matrix.
43 and 44 may be of any suitable supporting construc- Although the envelopment of stages subsequent to the
tion, such as fiberboard, metal screen, foil discs or the first or starting stage in relatively less combustible ma-
like. The downstream barrier 44 is a cap which actually 10 terial is one essential part of the invention, it iis to be un-
covers the inner end of tubular container 41, at a plane derstood that a second essential feature iis the structural
transverse to the igniter housing 31 substantially flush distribution of the different types of pellet materials.
with the inner opening of the igniter housing cup 32. They are not placed at random, but are arranged with a
The second-stage ignition charge 45 is comprised of first-stage readily ignitible core enclosed in, or surrounded
coated pellets 39 and substantially fills the ignition hous- 15 by, or at least partially surrounded by a second-stage or
ing cap 33 except for a thick layer of plastic foam (such several later stages of enveloped material.
as Styrofoam) cushioning 46 between the second-stage The preferred form makes use of the core and annulus
ignition charge 45 and the interior wall surface of the arrangement.
inner end of the ignition housing cap 33. Both the sec- Furthermore, it is a preferred species to employ the
ond-stage ignition charge 45 and the cushioning layer 20 arrangement of FIGURE 2 ,in which the solid annular
46 are enclosed in a moisture-impervious liner 47 and a matnix is actually separated from the first-stage ignition
disc shaped sheet 48 covering the contents of the cap charge 40 by a metal combustion resistant tube 41. How-
33 and protecting them from exposure. It will be seen ever, it will be appreciated, that tube 41 might be con-
that the liner 47 extends into a flange 49 which serves as structed of material which had very little resistance, or
a gasket between the threaded cap 33, and the externally 25 might be dispensed with entirely if no intermediate-stage
threaded cup 32. 45 were used; in that event, the combustion would spread
The third-stage ignition charge 50 is comprised of a from the igniter core 40 directly to the solid matrix 52,
large number of relatively small uncoated rapidly burn- and the pellets 51 therein, in the same manner as occurs
ing pellets 51 embedded in a solid matrix 52 of com- in the embodiment of FIGURE 1.
bustible material which may be the same as propellant 30 Although I have descriibed and rillustrated two specific
63 and 64 or have burning properties intermediate be- embodiments of my invention, it will be understood that
tween the propellant fuel and that of the ignition pellets those skilled in the engineering arts of ordnance and ex-
51. It will be seen that the matrix 52 is an annular body plosives will be able to conceive of many variations of
filling the lower part of the space between the exterior the ,invention without departing from its spirit. I there-
of the tubular container 41 and the interior surface of 35 fore intend that the scope of the invention be defined not
the cup 32. The most convenient method of manufac- by the detailed limitations set forth in the description
ture is to place the tubular container 41 in position, and of the embodiments of FIGURES 1 and 2, but by the
fill the annular space in cup 32 to the desired depth with terms of the following claim.
the matrix material in liquid form. The combustible Having thus described my invention, what I claim as
pellets 51 are then inserted into the liquid matrix ma- 40 new and desire to secure by Letters Patent is:
terial, which is then permitted to solidify into the third- . A propellent igniter for projecting a stream of thot ignit-
stage ignition charge 50. mg gas onto prope11ant, which igniter includes: a sub-
It is a preferred species of the invention to insure the stantially cyHndr,ical igniter housing having a nozzle end
proper ignition of the third-stage ignition charge 50 by and a squib end, said housing having sufficient bursting
placement of the upper layer of the pellets 51 with ex- 45 strength to remain intact during burning of igniter mate-
posed edges 53 projecting above the upper surface of the rials in its interior; walls defining a plurality of nozzle
solid matrix 52. ~- openings in said nozzle end for directing ignition gases
An annular cushion 54 of plastic foam (such ,as Styro- toward the propellant to be ignited; a tubular initial stage
foam) covers the exposed edges 53 of the third-stage igni- char~e container extending into the interior of said igniter
tion pellets 50 and cushions them from the intermediate 50 housmg from the central part of said squib end and hav-
stage coated pellets 39. ing an opening for discharge toward the interi~r of said
In operatiion, the igmter is actuated by the heating of nozzle. end; sa~d container having an annular space be-
the squib means 36. The heat in turn flash ignites squib tween its extenor walls and the interior side walls of said
powder charge 36b contained in the recess 42 under the ~gnit~r ~ousing; an initial iigniter charge of riapidly burn-
upstream barrier 43. The first-stage ignition charge 40 55 mg 1gmter material located in said tubular contaiiner·
is rapidly ignited, and rapidly burns through the down- ~quib ~ea~~ mounted in the squib end of said igniter hous~
stream barrier 44 to ignition of the second-stage ignition
mg for 1grut10n of said initial igniter charge; a middle stage
charge 45. Combustion of the second-stage ignition o~arge. of pellets slower-burning than said initial charge,
charge 45 is prolonged because it ris comprised of rela-
~ively large coated ignition pellets 39. 60 sa1d m1ddle stage charge being located in the nozzle end
As ignition of the second-svage ignition charge 45 pro- ?f s_aid igniter housing and in the path of ignition gases
ceeds, tJhe cushions 46 and 54 are rapidly consumed arid 1ssumg from the discharge opening of said tubular con-
ignition of the exposed edges 53 of the third-stage !igni- tainer; a final stage igniter charge in the form of an annu-
tion charge 50 occurs. The burning of the third ignition Jar ring located in said annular space between said tubu-
stage 50 is most prolonged of all the stages because of the 65 lar container and the inner side walls of said igniter hous-
envelopment of the pellets 51 in the solid matrix of rela- ing, said final stage igmter charge being comprised of a
tive,ly slow burning material 52. The precise nature of large number of rapid burning igniter pellets embedded
its burning can be determined by the mixture of solid in a solid matrix of material slow burning relative to said
matrix 52 ,and quick burning pellets 51. embedded pellets, with many of said rapid burning igniter
It will be seen from the foregoiing that I have provided
an igniter which functions as if it had three stages of igni- 70 pellets having exposed portions projecting from the sur-
face of said solid matdx toward said middle stage igniter
tion charge, by virtue of the construction of the ,igniter charge; and a layer of cushioning material between said
charge. The multi-stage effect is ,achieved by enveloping middle stage charge and said final stage ,igniter charge.
at least some of the pellets of the ignition charge in rela-
tively less combustible material. In the embodiment of 75 (References on following page)