U.S. patent application number 09/932725 was filed with the patent office on 2003-02-20 for telescoping pressure-balanced gas generator launchers for underwater use.
Invention is credited to Cipolla, Jeffrey L., MacLeod, Brenda Brennan.
Application Number | 20030033926 09/932725 |
Document ID | / |
Family ID | 25462802 |
Filed Date | 2003-02-20 |
United States Patent
Application |
20030033926 |
Kind Code |
A1 |
MacLeod, Brenda Brennan ; et
al. |
February 20, 2003 |
TELESCOPING PRESSURE-BALANCED GAS GENERATOR LAUNCHERS FOR
UNDERWATER USE
Abstract
A launching apparatus including a launch tube having a fore end
and an aft end, each end having an opening formed therein. A muzzle
cap is fit to the fore end of the launch tube and a breech mounting
is formed at the aft end of the launch tube. A primary plenum
housing is seated in the aft end of the launch tube, the primary
housing having a fore end and an aft end. A first telescoping
cylinder is initially positioned within the fore end of the primary
housing and a second telescoping cylinder is initially positioned
within the aft end of the primary housing. A first telescoping
piston is formed in the first telescoping cylinder and a second
telescoping piston formed in the second telescoping cylinder. A ram
plate is connected to the first telescoping piston and the second
telescoping piston is connected to the breech mounting. A gas
generator is provided within said primary housing and a projectile
is seated between the ram plate and the muzzle cap. The first and
second telescoping cylinders and the first and second telescoping
pistons expand in multiple stages of extension from the main
housing and propel the projectile.
Inventors: |
MacLeod, Brenda Brennan;
(Nashua, NH) ; Cipolla, Jeffrey L.; (Newport,
RI) |
Correspondence
Address: |
Naval Undersea Warfare Center
Division, Newport
Office Of Counsel, Bldg 112T
1176 Howell Street
Newport
RI
02841-1708
US
|
Family ID: |
25462802 |
Appl. No.: |
09/932725 |
Filed: |
August 20, 2001 |
Current U.S.
Class: |
89/1.81 |
Current CPC
Class: |
F41F 3/10 20130101; F41F
3/04 20130101; F41F 3/07 20130101 |
Class at
Publication: |
89/1.81 |
International
Class: |
F41F 003/00 |
Goverment Interests
[0001] The invention described herein may be manufactured and used
by or for the Government of the United States of America for
governmental purposes without the payment of any royalties thereon
or therefor.
Claims
What is claimed is:
1. A launching apparatus comprising: a launch tube having a fore
end and an aft end, each end having an opening formed therein; a
muzzle cap fit to the fore end of said launch tube; a breech
mounting formed at the aft end of said launch tube; a primary
housing positioned in the aft end of said launch tube forward of
said breech mounting, said primary housing having a fore end and an
aft end; a first telescoping cylinder slidably positioned within
the fore end of said primary housing; a second telescoping cylinder
slidably positioned within the aft end of said primary housing; a
first telescoping piston slidably disposed in said first
telescoping cylinder; a second telescoping piston slidably disposed
in said second telescoping cylinder and joined to said breech
mounting; a gas generator provided within said primary housing
between said first telescoping cylinder and said second telescoping
cylinder; a ram plate positioned in said launch tube and connected
to said first telescoping piston; and a projectile seated between
said ram plate and said muzzle cap.
2. The apparatus according to claim 1 wherein said muzzle cap and
said ram plate form a fluid tight seal against said launch tube
preventing entry of environmental elements.
3. The apparatus according to claim 1 wherein: said first
telescoping cylinder includes a first end having an outwardly
flanged end wall and a second end opposite the first end; and said
primary housing having a fore end stop flange positioned in said
primary housing fore end, said first telescoping cylinder outwardly
flanged end wall engaging with said fore end stop flange of said
primary housing on extension of said first telescoping
cylinder.
4. The apparatus according to claim 3 wherein said first
telescoping piston includes: a piston head slidable between the
first and second ends of said first telescoping cylinder; and a
piston shaft connected at one end to said ram plate and at the
other end to said piston head, said piston shaft being slidably
supported within the second end of said first telescoping
cylinder.
5. The apparatus according to claim 3 wherein: said second
telescoping cylinder includes a first end having an outwardly
flanged end wall and a second end opposite the first end; and said
primary housing having an aft end stop flange positioned in said
primary housing aft end, said second telescoping cylinder outwardly
flanged end wall engaging with said aft end stop flange of said
primary housing on extension of said second telescoping
cylinder.
6. The apparatus according to claim 5 wherein said second
telescoping piston includes: a piston head slidable between the
first and second ends of said second telescoping cylinder; and a
piston shaft connected at one end to said piston head and at the
other end to said breech mounting, said piston shaft being slidably
supported within the second end of said second telescoping
cylinder.
7. An expandable plenum assembly for a launching apparatus
comprising: a plenum housing having a fore end and a breech end,
said fore end having an inwardly extending fore end wall positioned
thereabout, and said breech end having an inwardly extending breech
end wall positioned thereabout; a first telescoping cylinder
initially positioned within the fore end of said plenum housing,
said first telescoping cylinder including a first end having a
flanged end wall, a second end opposite the first end having an
inwardly extending second end wall; a first piston slidable within
said first telescoping cylinder having a first piston head and a
first piston shaft connected to the first piston head; a second
telescoping cylinder initially positioned within the breech end of
said plenum housing, said second telescoping cylinder including a
first end having a flanged end wall, a second end opposite the
first end having an inwardly extending second end wall; a second
piston slidable within said second telescoping cylinder having a
second piston head and a second piston shaft connected to the
second piston head; and a gas generator positioned within said
plenum housing between said first telescoping cylinder first end
and said first piston head toward said fore end and said second
telescoping cylinder first end and said second piston head toward
said breech end.
8. The expandable plenum assembly according to claim 7 wherein upon
activation of said gas generator: said first telescoping cylinder
extends to an exterior of said plenum housing until said first
telescoping cylinder flanged end wall interferes with said plenum
housing fore end wall; said first piston shaft extends to an
exterior of said first telescoping cylinder until the first piston
head interferes with said first telescoping cylinder second end
wall; said plenum housing slides over said second telescoping
cylinder until said plenum housing breech end wall interferes with
said second telescoping cylinder flanged end wall; and said second
piston shaft extends to an exterior of said second telescoping
cylinder until said second piston head interferes with said second
telescoping cylinder second end wall.
9. A linear actuator comprising: an actuator housing having a
second end, a first end, and a wall portion extending between said
second end and first end, said second end being sealed, said first
end having a member aperture formed therein, and said sealed second
end and wall portion defining a hollow interior portion; an
intermediate member slidably disposed in said actuator housing
hollow interior portion and having a second end oriented toward
said actuator housing second end, a first end extending out of said
actuator housing member aperture, and a member wall extending
between said member first end and said member second end, said
member wall defining a hollow member interior portion, and said
member first end having a piston shaft aperture formed therein; a
piston slidably disposed in said intermediate member having a
piston head positioned in said hollow member interior portion and a
piston shaft extending out of said member piston shaft aperture;
and a gas generator positioned within said actuator housing second
end between said sealed actuator housing second end and said
intermediate member second end.
10. The apparatus of claim 9 wherein: said actuator housing has an
actuator housing internal flange positioned at said actuator
housing first end and extending inward into said member aperture;
said intermediate member has a member external flange positioned at
said member second end and conforming with said actuator housing
wall portion, said intermediate member further has a member
internal flange positioned at said member first end extending
inward into said piston shaft aperture; said piston head interferes
with said member internal flange for retaining said piston within
said intermediate member on extension of said piston; and said
intermediate member external flange interferes with said actuator
housing internal flange for retaining said intermediate member
within said actuator housing on extension of said intermediate
member.
11. The apparatus of claim 10 wherein: said actuator housing
internal flange has a housing pressure equalization port formed
therein allowing communication of environmental fluid between an
external environment and said actuator housing hollow interior
portion; and said intermediate member internal flange has a member
pressure equalization port formed therein allowing communication of
environmental fluid between the external environment and said
hollow member interior portion.
12. The apparatus of claim 11 further comprising a housing pressure
check valve positioned in said housing pressure equalization port
allowing communication between said actuator housing hollow
interior portion and the external environment when pressure in said
actuator housing hollow interior portion exceeds that in the
external environment.
13. The apparatus of claim 11 further comprising an intermediate
member pressure check valve positioned in said member pressure
equalization port allowing communication between said hollow member
interior portion and the external environment when pressure in said
hollow member interior portion exceeds that in the external
environment.
14. The apparatus of claim 9 wherein: said actuator housing is
cylindrical and has a cylindrical actuator housing hollow interior
portion; said intermediate member is cylindrical and has a
cylindrical member hollow interior portion; and said piston head is
cylindrical.
Description
BACKGROUND OF THE INVENTION
[0002] (1) Field of the Invention
[0003] This invention generally relates to a pressure balanced gas
generator launcher.
[0004] More particularly, the invention relates to a pressure
balanced gas generator launcher having telescoping elements capable
of extending the provision of launch forces.
[0005] (2) Description of the Prior Art
[0006] Currently, pressure balanced gas generator launchers are
under development. Ramming length limitations require that the gas
generator accelerate the projectile very rapidly in order to
provide the required launch speed. These relatively high
accelerations require that the projectile be designed to very high
shock standards. Thus, a problem exists in the art whereby it is
necessary to develop launchers providing high accelerations in
order to accommodate those projectiles requiring a high launch
speed.
[0007] The following patents, for example, disclose various types
of launchers, but do not disclose a gas generator launcher as does
the present invention which utilizes extended expansion from a
single primary cylinder housing.
[0008] U.S. Pat. No. 3,256,777 to Choate et al.;
[0009] U.S. Pat. No. 3,371,578 to Choate et al.;
[0010] U.S. Pat. No. 3,745,876 to Rocha;
[0011] U.S. Pat. No. 3,859,890 to Guthrie;
[0012] U.S. Pat. No. 4,037,821 to Greene;
[0013] U.S. Pat. No. 4,531,445 to Nee;
[0014] U.S. Pat. No. 4,616,554 to Spink et al.; and
[0015] U.S. Pat. No. 5,398,588 to Peck.
[0016] Specifically, Choate et al. '777 disclose a rocket launcher
having first and second tubular sections that are telescopingly
connected to enable the launcher to be extended into an elongated
position of use from a shortened, inoperative position with the
first section being the breech end and fitting within the second
section. During movement of the launcher sections from a
predetermined partly extended position into a fully extended
position, the firing member is moved into its cocked position, the
firing spring becomes operatively tensioned, and the launcher
sections become locked together.
[0017] The patent to Choate et al. '578 discloses a rocket launcher
of the type having first and second tubular sections telescopingly
connected, to enable them to be extended from a shortened
inoperative position into an elongated operative position.
[0018] The general objective of Choate et al. '578 is to provide
that type of launcher with improved safety features and to provide
basic constructions for those in production of launchers whether
the rockets to be launched therefrom are to be ignited by
percussion or electrically and also in the production of launchers
for use in firing sub-caliber practice rounds.
[0019] Rocha discloses a telescopic firearm including a firing tube
for the discharge of a projectile, a blast deflector, a flash
deflector for receiving said firing tube and blast deflector when
telescoped thereinto, covers mounted by hinges on said flash
deflector for closing the ends thereof, and a sight system
incorporated in said covers.
[0020] Guthrie discloses a projectile launching device in which a
projectile or warhead is mounted in an ejection tube in the form of
a piston and the ejection tube is mounted in a launching tube. A
propellant charge in the ejection tube supplies gas pressure to the
projectile to force the projectile out the ejection tube, and a
rocket nozzle located to the rear of the propellant charge receives
gases from a combustion of propellant charge to eject the ejection
tube from the launching tube.
[0021] The patent to Greene discloses a telescoping retractor
comprised of a two stage cylinder assembly actuated by an
electroexplosive power cartridge. A pair of cylinders are mounted
in concentric relation. A piston rod is carried in the inner
cylinder. The power cartridge produces the gas which sequentially
retracts the outer cylinder, the inner cylinder and then the piston
which is secured to the structure to be retracted.
[0022] Nee discloses a projectile launcher having first and second
telescopingly connected sections enabling it to be extended into an
operative state when it is to be discharged. The firing mechanism
has a firing member carried by the first section which extends into
a housing on the second section. The rear of the housing is a
chamber for a pivoted trigger having a forward portion of greater
length than its rearward portion and underlying a boot covered
part. A rotary sear in the chamber has first and second arcuately
spaced shoulders the second of which is engaged and held by the
rearward trigger portion under the influence of a spring. When but
a short further relative movement between the sections is required
to fully extend the launcher, the first sear shoulder engages and
pulls forward the firing member thus to cock the firing mechanism
when the launcher is fully extended, the firing spring then
exerting a substantial force against the first shoulder. While the
difference in lengths of the trigger portion offers the user a
theoretical mechanical advantage, the place where the effective
pressure of the fingers applied thereagainst through the boot is an
uncertain and variable factor causing inaccuracy in use due to the
resulting variations in the force required to pull the trigger. The
radial distances of the sear shoulders are such that the force
exerted by the second sear shoulder is so reduced that said factor
is minimized to an extent enabling the use of such launchers to be
attended with increased accuracy.
[0023] The patent to Spink et al. discloses an extendable rocket
launcher tube for a rocket wherein releasable telescoped concentric
inner and outer tubes house the rocket. Upon ignition, the rocket
releases the inner tube from the outer tube and carries it forward
imparting momentum thereto. The rocket is released from the inner
tube at a selected axial extension of the inner tube. The
components move at relative speeds such that acceleration of the
rocket is complete when the launcher tube is fully extended.
[0024] Peck discloses a missile launching system for launching a
missile including an automatically telescoping launch tube and a
restraining system. The telescoping launch tube lengthens the
period of guided travel of the missile during launch, to improve
its accuracy. The launch tube system has an outer case and an inner
launch tube internally dimensioned to receive the missile therein
and externally dimensioned to slide within the outer case from a
rearward position to a forward position. The restraining system
holds the missile and inner launch tube at the proper locations
before and during firing, and includes a releasable holdback for
the inner launch tube at the rearward position and a releasable
holdback for the missile at a preselected position within the inner
launch tube. The inner launch tube is restrained so that it may not
slide past the forward position relative to the outer case at the
end of its travel during the launching sequence.
[0025] It should be understood that the present invention would in
fact enhance the functionality of the above patents by providing
substantial additional extension from a single primary cylinder
housing by permitting staged and advancing telescoping functions
from both ends of the primary cylinder housing. The primary housing
holds plural internal cylinders which selectively expand in
reaction to a gas generator.
SUMMARY OF THE INVENTION
[0026] Therefore it is an object of this invention to provide a gas
generator launching apparatus.
[0027] Another object of this invention is to provide a gas
generator launching apparatus having reduced launch
acceleration.
[0028] Still another object of this invention is to provide a gas
generator launching apparatus capable of providing the necessary
launch velocity from a compact space.
[0029] A still further object of the invention is to provide a gas
generator launching apparatus in which internal and external
pressures are balanced for functioning in pressurized
environments.
[0030] Yet another object of this invention is to provide a gas
generator launching apparatus having an extended ramming length for
use in an underwater environment.
[0031] In accordance with one aspect of this invention, there is
provided a launching apparatus including a launch tube having a
fore end and an aft end, each end having an opening formed therein.
A muzzle cap is fit to the fore end of the launch tube and a breech
mounting is formed at the aft end of the launch tube. A primary
plenum housing is seated in the aft end of the launch tube, the
primary housing having a fore end and an aft end. A first
telescoping cylinder is initially positioned within the fore end of
the primary housing and a second telescoping cylinder is initially
positioned within the aft end of the primary housing. A first
telescoping piston is positioned in the first telescoping cylinder,
and a second telescoping piston is positioned in the second
telescoping cylinder. A ram plate is connected to the first
telescoping piston, and the second telescoping piston is connected
to the breech mounting. A gas generator is provided in connection
with said primary housing. A projectile is seated between the ram
plate and the muzzle cap. The first and second telescoping
cylinders and the first and second telescoping pistons expand in
multiple stages of extension from the main housing and propel the
projectile.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The various objects, advantages and novel features of this
invention will be more fully apparent from a reading of the
following detailed description in conjunction with the accompanying
drawings in which like reference numerals refer to like parts, and
in which:
[0033] FIG. 1 is a side sectional view of a launcher configuration
according to the present invention;
[0034] FIG. 2 is a side sectional view of a telescoping plenum
assembly schematic in pre-launch according to a preferred
embodiment of the present invention;
[0035] FIG. 3A is a schematic diagram showing a first stage of
launch;
[0036] FIG. 3B is a schematic diagram showing a second stage of
launch;
[0037] FIG. 3C is a schematic diagram showing a third stage of
launch;
[0038] FIG. 3D is a schematic diagram showing end of launch;
and
[0039] FIG. 4 is a schematic diagram showing an alternative
embodiment of a launcher configuration according to the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0040] In general, the present invention is directed to a
telescoping pressure-balanced gas generator launcher. The primary
purpose of a pressure-balanced gas generator launcher is to
increase the ramming length over that of the non-telescoping
pressure-balanced gas generator. By increasing the ramming length,
the necessary acceleration is reduced for projectiles requiring
high exit velocities.
[0041] Referring first to FIG. 1 of the present invention, the
telescoping pressure-balanced gas generator launcher is generally
illustrated at 10. The launcher 10 includes a fore end 12, an 1
aft/breech end 14, and an elongate housing portion 16. The fore end
12 of the launcher 10 has an opening 18 formed therein. Before
launch, the opening 18 is blocked by a removable muzzle cap 20. The
muzzle cap 20 is surrounded by sealing members 22 thereby providing
a water tight seal for an interior of the elongate housing 16 of
the launcher 10. The aft end 14 of the housing 16 includes a
partial end wall or strut, also referred to as a breech mounting
24. An opening 26 allows communication of environmental fluid such
as seawater 34 into the aft end 14 of housing 16.
[0042] A telescoping plenum assembly 28 is located adjacent the aft
end 14 of the housing 16 and is connected at one end to the breech
mounting 24 and at its opposite end to a ram plate 30. Prior to
use, the telescoping plenum assembly 28 is surrounded by seawater
34. A launch projectile 32 is seated within the housing 16 between
the ram plate 30 and the muzzle cap 20. The ram plate 30 is sealed
against an inner surface 17 of the housing 16 with sealing member
22 which prevent seawater 34 from contacting the launch projectile
32.
[0043] Referring now to FIG. 2, the telescoping plenum assembly 28
includes key components of the launcher configuration by
incorporating staged and multiple expansions of elements therein.
Specifically, the telescoping plenum assembly 28 is formed as a
single main cylinder 38 having a first end 40 and a second end 42.
An opening 44 is formed in the first end 40 and an opening 46 is
formed in the second end 42 of the plenum assembly 28.
[0044] At least two telescoping cylinders are housed within the
plenum assembly 28. One of the telescoping cylinders is a first
inner cylinder 50 and another of the telescoping cylinders is a
second inner cylinder 52. The first inner cylinder 50 includes a
distal end 54 and a proximate end 56, such that the distal end 54
terminates in the opening 44 of the main cylinder 38. The second
inner cylinder 52 also includes a proximate end 58 and a distal end
60, such that the distal end 60 terminates in the opening 46 of the
main cylinder 38. Sealing rings 23 or similar appropriate devices
are provided at the distal end 54 of the first inner cylinder 50
and at the distal end 60 of the second inner cylinder 52 to seal
out the external environment of, for example, seawater 34.
[0045] The proximate end 56 of the first inner cylinder 50 and the
proximate end 58 of the second inner cylinder 52 terminate in a
flange 62, 64, respectively. Flange 62 includes an outward radial
portion 62a and an inner rib 62b. The outward radial portion 62a is
in surface contact with the inner surface 17 of the housing 16 and
the inner rib 62b is smaller in diameter than an inner diameter of
the first inner cylinder 50. A first piston member having a piston
head 66 and a piston shaft 68 is slidably positioned within the
first inner cylinder 50 such that in a retracted position the
piston head 66 abuts the inner rib 62b of the flange 62. A distal
end of the first piston shaft 68 is connected to the ram plate
30.
[0046] Flange 64 includes an outward radial portion 64a and an
inner rib 64b. The outward radial portion 64a is in surface contact
with the inner surface 17 of the housing 16 and the inner radial
portion 64b is smaller in diameter than an inner diameter of the
second inner cylinder 52. A second piston member having a piston
head 70 and a piston shaft 72 is formed within the second inner
cylinder 52 such that the piston head 70 abuts the inner rib 64b of
the flange 64. A distal end of the second piston shaft 72 is
connected to the breech mounting 24. Each piston head 66, 70 is
slidably sealed by seal 25 within its respective inner cylinder 50,
52. A gas generator 36 is positioned in a plenum 99 within housing
16 between the first inner cylinder 50 and the second inner
cylinder 52. Gas generator 36 can be activated by any control
apparatus well known in the art.
[0047] With the arrangement of elements as described, it will be
understood that the first inner cylinder 50 is telescopingly
slidable through the opening 44 of the main cylinder 38, and the
shaft 68 of the first piston is telescopingly slidable through the
outer opening 50a of the first inner cylinder. Likewise, the second
inner cylinder 52 is telescopingly slidable through the opening 46
of the main cylinder 38, and the shaft 72 of the second piston is
telescopingly slidable through the outer opening 52a of the second
inner cylinder 52.
[0048] Upon complete expansion of the plenum assembly 28, the outer
flanged portion 62a of the first inner cylinder 50 is in contact
with an inner end surface 17a of the main cylinder 38, the piston
head 66 of the first piston is in surface contact with the outer
opening 50a of the first inner cylinder 50, the flanged portion 64
of the second inner cylinder 52 is in surface contact with the
inner breech end 17b of the main cylinder 38, and the piston head
70 of the second piston member is in surface contact with the outer
opening 52a of the second inner cylinder 52.
[0049] FIGS. 3A, 3B, 3C, and 3D illustrate the operation of the
launcher device 10. It should be noted that the expansion of the
plenum/piston stages does not necessarily occur in the order of
these FIGS., and may in fact occur simultaneously.
[0050] In FIG. 3A, when the gas generator 36 pressurizes the plenum
99, the first inner cylinder 50 and corresponding piston slide
forward inside the main cylinder 38, pushing the ram-plate 30,
projectile 32, and muzzle cap 20 out of the launch tube 10. In FIG.
3B, the first inner cylinder 50 catches once the flange 62 reaches
the first end 40 of the main cylinder 38, but the first piston
continues to slide forward until the head 56 reaches the outer end
50a of the first inner cylinder 50. In FIG. 3C, the main cylinder
38 begins to move forward dragged by the flange 62 of the first
inner cylinder 50. When the aft end 42 of the main cylinder 38
catches on the flange 64 of the second inner cylinder 52, the
second inner cylinder 52 begins sliding forward. In FIG. 3D, the
plenum 99 continues to expand (and push out the projectile 32)
until the outer end 52a of the second inner cylinder 52 catches on
the second piston head 70. Pistons and cylinders are sealed against
each other as shown with sealing members 22, 23.
[0051] Since ocean pressure acts on both ends of the projectile 32
(through the muzzle cap 20 and the ram plate 30), the gas generator
36 need only supply enough energy to overcome losses, expand the
volume of the plenum assembly 28, and accelerate the stages of the
telescoping plenum assembly 28, the ram plate 30, the projectile
32, and the muzzle cap 20. The key to keeping this launcher truly
pressure-balanced is minimizing the volume of the telescoping
cylinders 50, 52. Otherwise, the gas generator 36 must do more work
against ocean pressure in order to expand the plenum assembly
28.
[0052] The launch tube 10 and breech mounting 14 are reusable since
they don't come in contact with the combustion products of the gas
generator 36. Depending on the nature of the combustion products,
the telescoping plenum 28 may also be reusable during a limited
lifetime.
[0053] FIG. 4 shows an alternate embodiment of the plenum assembly
28 of the current invention. This embodiment provides a main
cylinder 100 having a single inner cylinder 102 and piston assembly
104. The main cylinder 100 is hollow and has a forward end 106 and
an aft end 108 with the aft end 108 being sealed and joined
directly to the breech mounting 24. The forward end 106 includes a
stop ring 110 positioned thereon such that the stop ring 110 has a
radius reduced from that of the main cylinder 100.
[0054] The inner cylinder 102 is likewise hollow and includes an
outwardly flanged aft end 112 and an inner cylinder forward end
114. The inner cylinder 102 is positioned within the main cylinder
100 such that the flanged aft end 112 is oriented toward the main
cylinder aft end 108. A gas source 116 is provided inside main
cylinder 100 and adjacent the flanged aft end 112 of the inner
cylinder 102. The flanged aft end 112 has an increased external
radius from the external radius of the inner cylinder 102. A
sliding fit exists between the flanged aft end 112 and an inner
surface of the main cylinder 100, and an outer periphery of the
flanged aft end 112 is sealed against the main cylinder 100 by a
plurality of sliding seals 118. The flanged aft end 112 also has a
shoulder 120 extending into the hollow portion of the inner
cylinder and thereby reducing the inner diameter thereof.
[0055] The forward end 114 of the inner cylinder 102 extends
through the stop ring 110 at the forward end 106 of the main
cylinder 100. The inner surface of the stop ring 110 has a bearing
surface therein allowing sliding of the inner cylinder 102 out from
the main cylinder 100. The forward end 114 of the inner cylinder
102 has a piston support flange 122 for narrowing the radius of the
interior surface of the inner cylinder 102. A plurality of fluid
communication ports 124 are provided in the piston support flange
122, thereby allowing communication between the environment and the
hollow interior of the inner cylinder 102.
[0056] The flanged aft end 112 and stop ring 110 bearing surface
prevent canting of the inner cylinder 102 with respect to the main
cylinder 100 by supporting the inner cylinder 102. A plurality of
fluid communication ports 126 are formed in the stop ring 110 to
allow environmental fluid to escape from the hollow portion
remaining between the main cylinder 100 and the inner cylinder 102
when the inner cylinder slides with respect to the main cylinder
100. Upon extension of the inner cylinder 102 from the main
cylinder 100, the increased radius of the flanged aft end 112
engages with the decreased radius of the stop ring 110, thereby
preventing the inner cylinder 102 from leaving the main cylinder
100.
[0057] Communication ports such as 124 and 126 are optional because
they introduce the risk of corrosion from seawater into the piston
assembly 104 and generate viscous drag as environmental fluid is
pushed out of the piston assembly 104. The pressure generated by
the gas source 116 is more than enough to overcome the back
pressure generated by gas trapped in between the cylinders 100 and
102. The back pressure has the benefit of preventing contact
between the flange 112 and stop ring 110 at the end of the piston
stroke. Check valves could be provided in communication ports 124
and 126 to prevent entry of seawater therethrough.
[0058] Piston assembly 104 including a piston 128 and a piston
shaft 130 is slidably disposed in the hollow portion of the inner
cylinder 102. The piston 128 is sealed against an inner surface of
the inner cylinder 102 with a sliding seal 132. The piston shaft
130 is joined to the piston 128 and extends forward through the
piston support flange 122. At its extreme forward end, the piston
shaft 130 is joined to the ram plate 30. When not extended, the
piston 128 is positioned against the shoulder 120 of the flanged
aft end 112. The piston support flange 122 engages with the piston
128 and prevents the piston assembly 104 from sliding out of the
hollow interior portion of the inner cylinder 102.
[0059] Upon activation of the gas source 116, pressure is generated
in a plenum defined between the surface created by the inner
cylinder flanged aft end 112 and piston 128 and the main cylinder
aft end 108. Generated pressure pushes the inner cylinder 102
forward from the main cylinder 100 and the piston assembly 104
forward from the inner cylinder 102. The ram plate 30 is pushed
outward by contact with the piston shaft 130. Environmental fluid
is expelled from the region between the main cylinder 100 and inner
cylinder 102 through fluid communication ports 126. Likewise, fluid
is expelled from the region between piston assembly 104 and inner
cylinder 102 through fluid communication ports 124.
[0060] These telescoping pressure balanced gas generator launcher
designs increase the ramming length of the non-telescoping
pressure-balanced launcher by a factor of two, which cuts the
average acceleration requirement by one-half.
[0061] Alternatives to this design of a telescoping pressure
balanced gas generator launcher include variations in the number of
telescoping cylinders and in the number of main cylinders
attachable to one another so as to multiply the ramming length.
Variations in cylinder/piston geometry also may occur (i.e. they
need not be truly "cylindrical"). Many different types of gas
generators could be used to pressurize the plenum.
[0062] In view of the above detailed description, it is anticipated
that the invention herein will have far reaching applications other
than those of underwater launch systems.
[0063] This invention has been disclosed in terms of certain
embodiments. It will be apparent that many modifications can be
made to the disclosed apparatus without departing from the
invention. Therefore, it is the intent of the appended claims to
cover all such variations and modifications as come within the true
spirit and scope of this invention.
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