Ammunition and explosives – Pyrotechnics – Flare
Reexamination Certificate
2000-07-19
2002-07-02
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Pyrotechnics
Flare
C102S254000
Reexamination Certificate
active
06412417
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a novel igniter assembly for igniting combustible compositions in a highly reliable manner, and in particular to an igniter assembly which includes a combustible illuminant composition and as actuated by deployment of an associated parachute. This invention also relates to devices comprising the novel igniter assembly, such devices including, by way of example, illuminating flares.
2. Description of the Related Art
Among the various environments in which illuminating flares are used, perhaps the most common environment for the use of flares involves the illumination of military battle grounds. In such applications, the flares are launched above ground or water areas suspected to contain enemy personnel and vehicles. Essentially, the illumination provided by the flare facilitates visual detection of the enemy personnel and vehicles, thereby providing more precise identification of target locations at which to aim arsenal. The illuminating effect provided by the flare is typically enhanced by equipping the flare with a parachute, which both increases the flight and time of descent for the illuminating flare and, upon deployment thereof, provides a requisite force for actuating an igniter housed in the flare.
The use of flares to ascertain the precise location of enemy targets can provide obvious military advantages. However, the availability and widespread use of military flares has negated this advantage somewhat, since there is an increased likelihood of opposing military forces also possessing flares. Thus, in order to gain a military advantage from the flares, it is paramount that the flares operate in a highly reliable and dependable manner, since flare failure can provide the opposing military force additional time to launch their own flares and arsenal.
An example of an illuminating flare that is reliable by conventional standards, e.g., about 87% of the time, is shown in
FIGS. 5-7
herein. It is believed that one of the largest contributors, if not the largest contributor, to failed firing of this illuminating flare is the misfiring of the flare igniter. The flare, which is generally designated by reference numeral
200
in
FIG. 5
, comprises an aluminum casing
202
partitioned into two compartments. The forward compartment is the larger of the two compartments, and contains a solid illuminant fuel
204
designed to enhance nighttime vision and an igniter assembly
206
for initiating burning of the illuminant fuel
204
. In the illustration, the aft compartment is the smaller of the two compartments, and contains a parachute
208
and a timing device (unnumbered). The timing device, inserted at an aft end of the casing
202
, detaches from the flare casing
202
at a predetermined time to create a passageway through which the parachute
208
can deploy. Upon deployment through the passageway, the parachute
208
slows the rate of descent of the flare
200
, thereby extending the time during which the burning illuminant fuel
204
is maintained at an elevated position. In this manner, the illuminating effect provided by the burning illuminant fuel
204
is enhanced.
A conventional igniter is disclosed in U.S. Pat. No. 4,155,306 and illustrated in
FIGS. 6 and 7
herein. Referring to
FIG. 6
, the igniter
206
includes a housing
212
formed of a molded piece of LEXAN (polycarbonate) or light-weight metal. The housing
212
has longitudinally extending internal walls
213
and ridge
213
a
, which are receivable into an aluminum cap (not shown). The internal walls
213
and the ridge
213
a
define upper and lower hollow compartments
215
, and a diametrically extending raceway
214
interposed between the upper and lower compartments
215
. The raceway is defined in part by the ridge
213
a
of the internal wall
213
. The ridge
213
a
has a depth less than that of the remainder of the internal walls
213
. For convenience, the ridge
213
a
is shaded. The function of the ridge
213
a
is explained in further detail below.
A sliding cartridge (also referred to herein as a slider)
216
is disposed in the raceway
214
and is slidable along the raceway
214
. The slider
216
comprises a spring-loaded striker arm
218
, a torsion spring (located at position
220
), and a pistol primer (containing small amount of explosive)
222
. The striker arm
218
is depicted in a loaded or cocked position in FIG.
6
. The torsion spring
220
urges the striker arm
218
to pivot about pin
224
and towards the position shown in
FIG. 7
, in which the striker arm
218
rests against the primer
222
. A cam surface
225
of the housing
212
obstructs the striker arm
218
from moving towards the primer
222
and, in combination with the urging force of the spring
220
, prior to actuation maintains the slider
216
in the position depicted in FIG.
6
.
Located below the raceway
214
is a pellet cavity
226
containing an ignitable composition, such as boron potassium nitrate (BKNO
3
) pellets. The pellet cavity
226
is in communication with the solid illuminant fuel
204
through an orifice (not shown).
The slider
216
is operatively connected to the parachute
208
via cable or lanyard
230
, which extends along a cable raceway (not shown) formed in the aluminum casing
202
. The cable
230
contains a first swage ball
232
accommodated within recess
234
for securing the cable
230
to the slider
216
. The recess
234
is in communication with a slot
236
, which is sufficiently wide to permit passage of the cable
230
, but to obstruct passage of the first swage ball
232
. At the end of the cable
230
is a second swage ball (not shown, but positioned behind the first swage ball
232
in FIG.
6
). The cable
230
extends between the first swage ball
232
and the second swage ball along an axial direction, that is, perpendicular to the portion of the cable
230
passing through the slot
236
(i.e., into the sheet on which
FIGS. 6 and 7
are shown). The second swage ball is encapsulated into the internal wall
213
. The encapsulation of the second swage ball in the internal wall
213
serves as a safety mechanism to protect against unintentional firing by preventing tension in the cable
230
from prematurely moving the slider
216
along the raceway
214
.
In operation, the igniter assembly
206
is actuated by the force generated upon parachute
208
deployment. Upon actuation of the parachute
208
, the deploying parachute pulls the cable
230
towards the aft end of the flare
200
. When properly operated, the force imparted on the cable
230
by the deploying parachute
208
is sufficient to dislodge the second swage ball from the housing
212
and move the slider
216
in tandem with striker arm
218
and the primer
222
across the raceway
214
with sufficient force to overcome the frictional resistance between the cocked striker arm
218
and the cam surface
225
, as well as the frictional resistance between the slider
216
and the raceway
214
, thus passing the striker arm
218
under the cam surface
225
.
After the slider
216
has moved a sufficient distance for the striker arm
218
to clear the cam surface
225
, the urging force of the torsion spring
220
pivots the striker arm
218
about pin
224
and towards the primer
222
, which is now located over the cavity
226
containing pellets. Impact of striker arm
218
against the primer
222
detonates the primer
222
. The heat and flames generated by the detonation of the primer
222
pass through an orifice and ignite the BKNO
3
pellets in cavity
226
, which in turn ignites a wafer, which in turn ignites the solid illuminant fuel
204
. Because the ridge
213
a
of the internal wall
213
extends in depth only a portion of the way across the depth of the raceway
214
, a clearance is defined (between the ridge
213
a
and the opposing cap surface) through which the striker arm
218
can pass as the striker arm
218
pivots towards the primer
222
.
Although effective by conventional standards, flares possessing th
Anderson Derek C.
Osterhout Ryan D.
Pond Mark H.
Alliant Techsystems Inc.
Jordan Charles T.
Smith Kimberly S.
Sullivan Law Group
LandOfFree
Igniter assembly actuated by parachute deployment, and flare... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Igniter assembly actuated by parachute deployment, and flare..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Igniter assembly actuated by parachute deployment, and flare... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2874818