Ammunition and explosives – Igniting devices and systems – Propellant ignitors
Reexamination Certificate
2002-08-01
2003-12-09
Tudor, Harold J. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Propellant ignitors
C102S202140, C102S204000, C102S470000, C102S530000, C280S741000
Reexamination Certificate
active
06659009
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates in general to gas generating initiators and in particular to gas generating initiators including a filter that prevents large particles from entering the generated gas stream.
FIG. 1
is a sectional view of a prior art gas generating initiator
10
. Initiator
10
may be used in applications such as the launching of sonobuoys from aircraft, ejector seats in aircraft and the initiation of ballistic munitions.
Initiator
10
includes a generally cylindrical body
12
that defines an initiator chamber
14
. The body
12
is open at one end
11
and closed at a second end by a base
13
. The body
12
has a central longitudinal axis A—A. The base
13
includes a generally centrally located passage
15
. Passage
15
has one end on an interior surface
17
of the base and a second end on an exterior surface
19
of the base. A longitudinal axis of the first passage
15
is substantially coincident with the axis A—A of the body
12
. Adhesive is applied to the threads of a filter
30
, discussed in more detail below, which is then threaded into passage
15
. Body
12
and filter
30
may be made of, for example, aluminum, aluminum alloy, steel or steel alloy.
Initiator
10
includes a charge holder
16
disposed in the open end
11
of the body
12
. The charge holder
16
includes a consumable membrane
18
at one end and gas generating propellant
20
disposed in the charge holder
16
. Charge holder
16
may be made of plastic and snap fit into chamber
14
. Consumable membrane
18
may be made of nitrocellulose. A cap
22
is attached to the open end
11
of the body
12
, by, for example, threaded engagement. An igniter
24
is disposed in an opening in the cap
22
and extends into the charge holder
16
. The igniter
24
ignites the propellant
20
in the charge holder
16
. A firing mechanism
26
is connected to the igniter
24
for firing the igniter. The firing mechanism may be activated, for example, manually or by a variety of switches, such as inertial switches, accelerometers, etc.
In ballistic applications, gas exiting the passage
15
is routed to a munition by using a nipple
28
attached (for example, with threads) to the base end
13
of the initiator body
12
. The nipple
28
includes a passageway
29
therethrough to provide a conduit for gas generated by the initiator.
FIGS. 2
a
-
2
c
show details of a prior art filter
30
.
FIG. 2
a
is a top view of the filter
30
showing a hexagonal head
32
.
FIG. 2
b
is a sectional view along the line b—b of
FIG. 2
a
.
FIG. 2
c
is a sectional view along the line c—c of
FIG. 2
b
. Head
32
is joined to a shank
34
. The shank
34
is threaded and threads into passage
15
. Head
32
includes five radial gas passages
36
that intersect in the center of head
32
. The five radial passages
32
join an axial passage
38
.
In use, the initiator
10
is operated by firing the firing mechanism
26
which sends an electric signal to igniter
24
. Igniter
24
ignites propellant
20
thereby generating gas. Consumable membrane
18
bursts and/or burns and the generated gas enters the filter
30
via the five radial passages
32
, then enters the axial passage
38
and then exits the initiator via passage
15
. The radial passages
32
in filter
30
are small enough to prevent any large particles of propellant or pieces of charge holder
16
from entering passage
15
.
Because of the relatively small size of initiator chamber
14
(diameter may be as small as 0.035 inches), it is difficult to machine the even smaller filter
30
. In addition, adhesive must be applied to the threads on filter
30
and then the filter must be threaded into the passage
15
. The present invention eliminates the separate filter
30
, thereby saving the time and money of fabricating filter
30
and assembling filter
30
into initiator
10
.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a gas generating initiator having a drilled-in integral multi-port filter.
It is another object of the invention to provide a gas generating initiator with fewer parts than the prior art to thereby simplify manufacture and assembly.
REFERENCES:
patent: 2995088 (1961-08-01), Asplund
patent: H124 (1986-09-01), Antonuzzi et al.
patent: 4856433 (1989-08-01), Evans
patent: 5192829 (1993-03-01), Suire
patent: 5496064 (1996-03-01), Osborne et al.
patent: 5634661 (1997-06-01), Dahl et al.
patent: 5675115 (1997-10-01), Hershkowitz et al.
patent: 6328337 (2001-12-01), Katsuda et al.
patent: 6338500 (2002-01-01), Perotto
patent: 2001/0042298 (2001-11-01), Katsuda et al.
patent: 315857 (1920-06-01), None
Homer Mark
The United States of America as represented by the Secretary of
Tudor Harold J.
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