U.S. patent application number 12/137187 was filed with the patent office on 2009-12-17 for integrated pusher plate for a canister- or gun-launched projectile and system incorporating same.
This patent application is currently assigned to LOCKHEED MARTIN CORPORATION. Invention is credited to Johnny E. Banks, Umang R. Patel, Wayne K. Schroeder.
Application Number | 20090308274 12/137187 |
Document ID | / |
Family ID | 41413575 |
Filed Date | 2009-12-17 |
United States Patent
Application |
20090308274 |
Kind Code |
A1 |
Schroeder; Wayne K. ; et
al. |
December 17, 2009 |
Integrated Pusher Plate for a Canister- or Gun-Launched Projectile
and System Incorporating Same
Abstract
A pusher plate assembly for launching a projectile includes a
pusher plate, a pressure seal circumferentially extending about the
pusher plate, a cage extending from an aft side of the pusher
plate, and a plurality of propellant portions disposed in the cage.
A projectile system includes a launching tube, a projectile
disposed in the launching tube, a pusher plate assembly disposed
between an aft end of the projectile and the launching tube, a
fuze, a charge igniter operatively associated with the fuze and the
plurality of propellant portions, and a retainer disposed within
the launching tube proximate a mouth of the launching tube. The
pusher plate assembly includes a pusher plate, a pressure seal
circumferentially extending about the pusher plate to seal an
annulus between the pusher plate and the launching tube, a cage
extending from an aft side of the pusher plate, and a plurality of
propellant portions disposed in the cage.
Inventors: |
Schroeder; Wayne K.;
(Mansfield, TX) ; Patel; Umang R.; (Mansfield,
TX) ; Banks; Johnny E.; (Venus, TX) |
Correspondence
Address: |
LAW OFFICES OF JAMES E. WALTON, PLLC
1169 N. BURLESON BLVD., SUITE 107-328
BURLESON
TX
76028
US
|
Assignee: |
LOCKHEED MARTIN CORPORATION
Dallas
TX
|
Family ID: |
41413575 |
Appl. No.: |
12/137187 |
Filed: |
June 11, 2008 |
Current U.S.
Class: |
102/464 ;
102/202 |
Current CPC
Class: |
F41F 3/04 20130101; F42B
5/105 20130101; F42C 19/0823 20130101 |
Class at
Publication: |
102/464 ;
102/202 |
International
Class: |
F42B 5/26 20060101
F42B005/26; F42C 19/08 20060101 F42C019/08 |
Claims
1. A pusher plate assembly for launching a projectile, comprising:
a pusher plate; a pressure seal circumferentially extending about
the pusher plate; a cage extending from an aft side of the pusher
plate; and a plurality of propellant portions disposed in the
cage.
2. The pusher plate assembly, according to claim 1, wherein the
cage is formed of wire mesh.
3. The pusher plate assembly, according to claim 1, wherein the
pressure seal comprises: an elastomer.
4. The pusher plate assembly, according to claim 1, wherein at
least some of the plurality of propellant portions comprises one or
more of a nitrate-based solid propellant and an aluminum-based
solid propellant.
5. The pusher plate assembly, according to claim 1, further
comprising: a projectile motor igniter; and a motor igniter
controller operatively associated with the projectile motor
igniter.
6. The pusher plate assembly, according to claim 5, wherein the
motor igniter controller includes an accelerometer.
7. The pusher plate assembly, according to claim 5, wherein the
motor igniter controller includes a position sensor.
8. The pusher plate assembly, according to claim 5, wherein the
motor igniter controller includes a timer.
9. A projectile system, comprising: a launching tube; a projectile
disposed in the launching tube; a pusher plate assembly disposed
between an aft end of the projectile and the launching tube, the
pusher plate assembly comprising: a pusher plate; a pressure seal
circumferentially extending about the pusher plate to seal an
annulus between the pusher plate and the launching tube; a cage
extending from an aft side of the pusher plate; and a plurality of
propellant portions disposed in the cage; a fuze; a charge igniter
operatively associated with the fuze and the plurality of
propellant portions; and a retainer disposed within the launching
tube proximate a mouth of the launching tube.
10. The projectile system, according to claim 9, wherein the cage
is formed of wire mesh.
11. The pusher plate assembly, according to claim 9, wherein the
pressure seal comprises: an elastomer.
12. The pusher plate assembly, according to claim 9, wherein at
least some of the plurality of propellant portions comprises one or
more of a nitrate-based solid propellant and an aluminum-based
solid propellant.
13. The pusher plate assembly, according to claim 9, further
comprising: a projectile motor igniter; and a motor igniter
controller operatively associated with the projectile motor
igniter.
14. The pusher plate assembly, according to claim 13, wherein the
motor igniter controller includes an accelerometer.
15. The pusher plate assembly, according to claim 13, wherein the
motor igniter controller includes a position sensor.
16. The pusher plate assembly, according to claim 13, wherein the
motor igniter controller includes a timer.
17. A method for launching a projectile from a launch tube,
comprising: providing a pusher plate assembly disposed between the
projectile and the launch tube, the pressure plate assembly
comprising: a pusher plate; a pressure seal circumferentially
extending about the pusher plate to seal an annulus between the
pusher plate and the launching tube; a cage extending from an aft
side of the pusher plate; and a plurality of propellant portions
disposed in the cage; igniting the plurality of propellant
portions; burning an opening in the cage with the ignited plurality
of propellant portions; urging the projectile with expanding gases
produced by the ignited plurality of propellant portions; and
allowing a progressively larger fraction of the plurality of
propellant portions to escape the cage as the pressure plate
assembly traverses within the launch tube.
18. The method, according to claim 17, further comprising: igniting
a motor of the projectile with a projectile motor igniter of the
pusher plate assembly.
19. The method, according to claim 18, further comprising:
operating the projectile motor igniter based on at least one of an
acceleration of the pusher plate assembly, a position of the pusher
plate assembly with respect to the launching tube, and an elapsed
time from ignition of the plurality of propellant portions.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to projectile launching
systems.
[0003] 2. Description of Related Art
[0004] Many modern projectiles, such as missiles, rockets, and the
like, are launched from canisters or guns. In some projectile
systems, thrust from a projectile's motor is used to launch the
projectile from a canister or gun. Using the projectile's thrust to
launch the projectile, however, reduces the amount of propellant
available to propel the projectile to its intended target.
[0005] In response to this problem, some projectile systems employ
a launching propellant, which is separate from the projectile's
propellant, to launch the projectile from the canister or gun and
to provide an initial velocity to the projectile. For example, FIG.
1 depicts a projectile system 101 in a pre-launch configuration.
Projectile system 101 includes a projectile 103 disposed in a
canister 105. Disposed between an aft end 107 of projectile 103 and
canister 105 is a propellant 109 and a pusher plate 111. When
projectile 103 is to be launched from canister 105, a propellant
igniter 113 is activated to ignite propellant 109. Expanding gases
generated by the burning propellant 109 urges pusher plate 111, and
thus projectile 103, generally in a direction corresponding to an
arrow 115. Shortly before projectile 103 exits canister 105 or upon
projectile 103 exiting canister 105, a projectile motor igniter 117
ignites a motor (not shown) of projectile 103. Thrust from the
projectile motor propels projectile 103 toward its intended
target.
[0006] It is desirable, however, for canister 105 to be as small as
possible to minimize the size of the overall projectile system and
to minimize cost. However, as shown in FIG. 2, the configuration of
projectile system 101 accelerates projectile 103 very quickly,
which often exceeds the acceleration rating of projectile 103.
Moreover, the acceleration of projectile undesirably decreases
substantially over distance.
[0007] To overcome this problem, as shown in FIG. 3, projectile 101
and pusher plate 111 are spaced away from propellant 109 to provide
a space 301 for propellant gases to initially accumulate, thus
decreasing the maximum acceleration, and particularly inhibiting an
acceleration spike, of projectile 103, as shown in FIG. 4. Such a
configuration, however, increases the overall length of canister
105 by a distance L, which is undesirable for at least the reasons
set forth above.
[0008] There are many designs of projectile launching systems well
known in the art, however, considerable shortcomings remain.
DESCRIPTION OF THE DRAWINGS
[0009] The novel features believed characteristic of the invention
are set forth in the appended claims. However, the invention
itself, as well as, a preferred mode of use, and further objectives
and advantages thereof, will best be understood by reference to the
following detailed description when read in conjunction with the
accompanying drawings, in which the leftmost significant digit(s)
in the reference numerals denote(s) the first figure in which the
respective reference numerals appear, wherein:
[0010] FIG. 1 is a stylized, side, cross-sectional view of one
particular conventional projectile system;
[0011] FIG. 2 is a graph illustrating a particular acceleration
versus distance curve for the projectile of the conventional
projectile system of FIG. 1;
[0012] FIG. 3 is a stylized, side, cross-sectional view of an
alternative conventional projectile system;
[0013] FIG. 4 is a graph illustrating a particular acceleration
versus distance curve for the projectile of the conventional
projectile system of FIG. 3;
[0014] FIG. 5 is a stylized, side, cross-sectional view of an
illustrative embodiment of a projectile system;
[0015] FIG. 6 is a stylized, side, elevational view of a pusher
plate assembly of the projectile system of FIG. 5; and
[0016] FIGS. 7-9 depict one particular embodiment of a method for
operating the projectile system of FIG. 5.
[0017] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof have been shown
by way of example in the drawings and are herein described in
detail. It should be understood, however, that the description
herein of specific embodiments is not intended to limit the
invention to the particular forms disclosed, but on the contrary,
the intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the invention
as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. It will of
course be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developer's specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure.
[0019] A pusher plate assembly for launching a projectile includes
a pusher plate, a pressure seal circumferentially extending about
the pusher plate, a cage extending from an aft side of the pusher
plate, and a plurality of propellant portions disposed in the
cage.
[0020] A projectile system includes a launching tube, a projectile
disposed in the launching tube, a pusher plate assembly disposed
between an aft end of the projectile and the launching tube, a
fuze, a charge igniter operatively associated with the fuze and the
plurality of propellant portions, and a retainer disposed within
the launching tube proximate a mouth of the launching tube. The
pusher plate assembly includes a pusher plate, a pressure seal
circumferentially extending about the pusher plate to seal an
annulus between the pusher plate and the launching tube, a cage
extending from an aft side of the pusher plate, and a plurality of
propellant portions disposed in the cage.
[0021] A method for launching a projectile from a launch tube
includes providing a pusher plate assembly disposed between the
projectile and the launch tube. The pressure plate assembly
includes a pusher plate, a pressure seal circumferentially
extending about the pusher plate to seal an annulus between the
pusher plate and the launching tube, a cage extending from an aft
side of the pusher plate, and a plurality of propellant portions
disposed in the cage. The method further includes igniting the
plurality of propellant portions, burning an opening in the cage
with the ignited plurality of propellant portions, urging the
projectile with expanding gases produced by the ignited plurality
of propellant portions, and allowing a progressively larger
fraction of the plurality of propellant portions to escape the cage
as the pressure plate assembly traverses within the launch
tube.
[0022] Referring to FIG. 5 in the drawings, an illustrative
embodiment of a projectile system 501 comprises a projectile 503, a
launching tube 505, a pusher plate assembly 507, a charge igniter
509, a fuze 511, and a retainer 513. It should be noted that
launching tube 505 may be any tube from which a projectile, such as
projectile 503, is launched, e.g., a projectile canister, a gun
barrel, or the like. Projectile 503 is disposed in launching tube
505 and, in certain embodiments, may be positioned within launching
tube 505 by conventional sabots or other such spacers, which are
not shown. It should be noted that, while projectile system 501 is
discussed herein as comprising launching tube 505, projectile
system 501 may alternatively comprise a gun or gun barrel from
which projectile 503 is launched. Pusher plate assembly 507 is
disposed between an aft end 515 of projectile 503 and launching
tube 505. Charge igniter 509 extends between fuze 511 and charge
igniter 509. Generally, pusher plate assembly 507 urges projectile
503 from launching tube 505 upon activation of charge igniter 509
by fuze 511 and ignites a motor 517 of projectile 503, as is
discussed in greater detail herein.
[0023] FIG. 6 depicts an enlarged view of one particular embodiment
of pusher plate assembly 507. It should be noted that elements of
projectile system 501 included in FIG. 6, with the exception of
pusher plate assembly 507, are depicted in phantom to better
illustrate pusher plate assembly 507. In the illustrated
embodiment, pusher plate assembly 507 comprises a pusher plate 601,
a pressure seal 603, a cage 605, a plurality of propellant portions
607, a projectile motor igniter 609, and a motor igniter controller
611. In one embodiment, however, projectile motor igniter 609 and
motor igniter controller 611 are omitted. In use, projectile 503
rests on or abuts pressure 601 and pressure seal 603 extends
between pusher plate 601 and launching tube 505, substantially
sealing an annulus 613 between pusher plate 601 and launching tube
505. Preferably, pressure seal 603 comprises an elastomer, such as
a silicone elastomer. Pusher plate 601, pressure seal 603, and
launching tube 505 define a substantially closed chamber 519 in
which the plurality of propellant portions 607 burns, as is
described in greater detail herein.
[0024] Still referring to FIG. 6, cage 605 extends from an aft side
615 of pusher plate 601. Preferably, cage 605 is formed of wire
mesh. Part of cage 605 is removed in FIG. 6 to better reveal the
plurality of propellant portions 607 disposed therein. The
plurality of propellant portions 607 comprises a solid propellant
or a combination of solid propellants; however, the particular
composition of propellant portions 607 is implementation specific.
In some embodiments, propellant portions 607 comprise a
nitrate-based solid propellant, while in other embodiments,
propellant portions 607 comprise an aluminum-based solid
propellant. For example, if the particular implementation lends
itself to the use of a high-energy propellant, an aluminum-based
propellant may be used. However, if smoke is not desirable at the
launch of a projectile, such as projectile 503, a non-aluminum
based propellant may be used. The plurality of propellant portions
607 may comprise any propellant material or combination of
propellant materials that are suitable, when activated, for urging
projectile 503 from launching tube 505. Preferably, the propellant
portions of the plurality of propellant portions 607 are generally
spherical in shape, but other shapes are contemplated by the
present invention.
[0025] Still referring to FIG. 6, motor igniter controller 611 is
attached to pusher plate 601 and is preferably disposed within
pusher plate 601. Motor igniter controller 611 is coupled with
projectile motor igniter 609, which extends into a nozzle 617 of
projectile motor 517, to control the activation of projectile motor
igniter 609, as is discussed in greater detail herein.
[0026] FIGS. 7-9 depict one particular embodiment of a method for
using projectile system 501. In FIG. 7, fuze 511 (shown in FIG. 5)
is initiated to activate, as represented by a graphic 701, charge
igniter 509 (shown in FIG. 5). Charge igniter 509 ignites at least
some of the plurality of propellant portions 607. At some point in
time after ignition, however, substantially all of the plurality of
propellant portions 607 are ignited. It should be noted that, at
ignition, the plurality of propellant portions 607 are preferably
packed in cage 605. Thus, initially, not all surfaces of the
plurality of propellant portions 607 are available for burning, as
some surfaces of the plurality of propellant portions 607 are in
contact with other surfaces of the plurality of propellant portions
607.
[0027] Still referring to FIG. 7, charge igniter 509 and/or the
ignited part of the plurality of propellant portions 607 burn
through cage 605, allowing some of the plurality of propellant
portions 607 to escape cage 605 into chamber 519. The burning
propellant portions of the plurality of propellant portions 607
create expanding gases that pressurize chamber 519. When the force
acting on pusher plate 601 and pressure seal 603 due to the
pressure generated by the expanding gases in chamber 519 exceeds
the force on pusher plate 601 and pressure seal 603 due to gravity
and friction between pressure seal 603 and launching tube 505,
pusher plate 601, pressure seal 603, projectile 503, the remaining
portion of cage 605, and the portion of the plurality of propellant
portions 607 remaining in cage 605 are urged in a direction
generally corresponding to an arrow 703.
[0028] Referring now to FIG. 8, as pusher plate 601 and pressure
seal 603 are urged in the direction generally corresponding to
arrow 703, a volume of chamber 519 increases, a larger portion of
cage 605 is burned away, and a greater fraction of the burning
plurality of propellant portions 607 escapes cage 605 into chamber
519. As more of the burning plurality of propellant portions 607
escapes into chamber 519, more propellant surface area is exposed
for burning, thus increasing the burning rate of the plurality of
propellant portions 607 and creating a greater volume of expanding
gases, which continue to pressurize chamber 519. As chamber 519
continues to be pressurized, pusher plate 601, pressure seal 603,
projectile 503, the remaining portion of cage 605, and the portion
of the plurality of propellant portions 607 remaining in cage 605
are further urged generally along arrow 703.
[0029] It should be noted that the burning surface area of the
plurality of propellant portions 607, and thus the burn rate of the
plurality of propellant portions 607, increases in relationship to
the fraction of the plurality of propellant portions 607 that
escape cage 605. Generally, chamber 519 increases in volume as a
larger fraction of the plurality of propellant portions 607 escapes
cage 605. This relationship provides a flatter acceleration curve
for projectile 501 than that shown in FIG. 2 and, in one
embodiment, provides an acceleration curve for projectile 501
corresponding to that shown in FIG. 4.
[0030] Referring now to FIG. 9, motor igniter controller 611 (shown
in FIG. 6) ignites projectile motor igniter 609, as represented by
a graphic 901, prior to projectile 503 fully exiting launching tube
505. Projectile motor igniter 609 extends into nozzle 617 of
projectile motor 517 to start projectile motor 517 when activated
by motor igniter controller 611. Motor igniter controller 611 may
be operated to control projectile motor igniter 609 using a variety
of sensed conditions. For example, in one particular embodiment,
motor igniter controller 611 comprises an accelerometer, such that
motor igniter controller 611 operates projectile motor igniter 609
when motor igniter controller 611 experiences acceleration at a
predetermined level. The predetermined acceleration level can be a
predetermined acceleration level in an upward trend of acceleration
levels or a predetermined acceleration level in a downward trend of
acceleration levels. In another embodiment, motor igniter
controller 611 comprises a position sensor, such that motor igniter
controller 611 operates when motor igniter controller 611 reaches a
certain location within launching tube 505, corresponding to a
desired location of projectile 503 with respect to launching tube
505. In one embodiment, the position sensor interacts with retainer
513, thus providing the sensory input to motor igniter controller
611 to operate projectile motor igniter 609. Alternatively, motor
igniter controller 611 comprises a timer, such that motor igniter
controller 611 operates projectile motor igniter 609 after a
predetermined period of time has elapsed following activation of
charge igniter 509. Other scenarios for operating motor igniter
controller 611, however, are contemplated by the present
invention.
[0031] Retainer 513 is fixedly disposed proximate a mouth 521 of
launching tube 505. Pusher plate 601, pressure seal 603, the
remaining portion of cage 605, and any portion of the plurality of
propellant portions 607 remaining in cage 605 are captured within
launching tube 505 by retainer 513 as projectile 503 exits
launching tube 505, thus inhibiting damage to equipment and
personnel about projectile system 501.
[0032] Advantages of the invention include, but are not limited to
(1) providing a means for launching a projectile from a launching
tube that manages the acceleration of the projectile without
increasing the size of the launching tube; (2) providing a means
for launching a projectile from a launching tube without requiring
a high axial acceleration tolerance of the projectile; and (3)
providing a means for launching a projectile that further includes
a means for igniting a motor of the projectile.
[0033] The particular embodiments disclosed above are illustrative
only, as the invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. Furthermore, no limitations
are intended to the details of construction or design herein shown,
other than as described in the claims below. It is therefore
evident that the particular embodiments disclosed above may be
altered or modified and all such variations are considered within
the scope and spirit of the invention. Accordingly, the protection
sought herein is as set forth in the claims below. It is apparent
that an invention with significant advantages has been described
and illustrated. Although the present invention is shown in a
limited number of forms, it is not limited to just these forms, but
is amenable to various changes and modifications without departing
from the spirit thereof.
* * * * *