U.S. patent application number 09/977905 was filed with the patent office on 2003-04-10 for self adjusting neutral buoyancy countermeasure and system.
Invention is credited to Dubois, Neil J..
Application Number | 20030068935 09/977905 |
Document ID | / |
Family ID | 25525626 |
Filed Date | 2003-04-10 |
United States Patent
Application |
20030068935 |
Kind Code |
A1 |
Dubois, Neil J. |
April 10, 2003 |
SELF ADJUSTING NEUTRAL BUOYANCY COUNTERMEASURE AND SYSTEM
Abstract
An underwater self adjusting displacement device includes a
sealed housing having an exterior wall and an inner component area,
the exterior wall having an opening formed therein. A sealing plug
is slidably seated in the opening of the exterior wall, and an
actuator mechanism selectively adjusts the sealing plug within the
opening, thereby adjusting a total displacement of the sealed
housing. The displacement device is incorporated into any
substantially neutrally buoyant underwater deployable device such
as an acoustic countermeasure device or an oceanographic sensor
device. Further, the deployable devices may be deployed
individually or as a field due. The displacement device requires
less weight and weight within an overall deployed device, enabling
large deployments and performance enhancements.
Inventors: |
Dubois, Neil J.; (Cranston,
RI) |
Correspondence
Address: |
Office Of Counsel
Naval Undersea Warfare Center Division, Newport
Bldg 112T
1176 Howell Street
Newport
RI
02841-1708
US
|
Family ID: |
25525626 |
Appl. No.: |
09/977905 |
Filed: |
October 10, 2001 |
Current U.S.
Class: |
441/6 |
Current CPC
Class: |
B63B 22/24 20130101;
B63B 22/18 20130101 |
Class at
Publication: |
441/6 |
International
Class: |
B63B 022/16 |
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. An underwater self adjusting displacement device comprising: a
sealed housing having an exterior wall and an inner component area,
the exterior wall having an opening formed therein; a sealing plug
slidably seated in the opening of the sealed housing exterior wall;
an actuator mechanism joined to move said sealing plug for
selectively adjusting said sealing plug within the sealed housing
opening, thereby adjusting a total displacement of said housing; a
pressure sensor joined to said sealed housing and exposed to
external fluid for determining an underwater depth of said device;
a salinity meter joined to said sealed housing and exposed to
external fluid for determining a salinity of said water; and a
controller in communication with said pressure sensor, said
salinity meter and said actuator mechanism for controlling said
actuator mechanism and said sealing plug in response to data from
said pressure sensor and said salinity meter.
2. The device according to claim 1 wherein said sealing plug is
shaped to conform to the opening of the exterior wall.
3. The device according to claim 2 wherein said sealing plug
comprises: a plug portion slidably positioned in said sealed
housing opening; and a sealing washer positioned around the
perimeter of the plug portion between said plug portion and said
sealed housing.
4. The device according to claim 1 wherein said actuator mechanism
comprises: a linear actuator joined to said controller; a shaft
joined between said linear actuator and said sealing plug; and a
bracket fixed to an inner surface of said sealed housing supporting
said actuator mechanism.
5. The device according to claim 1 wherein said actuator mechanism
comprises: a motor joined to said controller; a drive gear
connected to and rotated by said motor; a power screw having thread
portions engaged with said drive gear at a first end thereof and
connected to said sealing plug at an opposing end thereof; and a
bracket fixed to an inner surface of said sealed housing supporting
said motor.
6. The device according to claim 5 wherein: said sealing plug has a
cavity formed within said sealing plug and an opening formed in a
surface of said sealing plug in communication with said cavity;
said power screw further including a plate member fixed to said
power screw opposing end, said plate member being positioned within
said sealing plug cavity, said plate member contacting said sealing
plug for moving said sealing plug.
7. The device according to claim 1 further comprising: a plurality
of transducer elements positioned within said sealed housing in
communication with environmental fluid; a power source positioned
within said sealed housing and joined to said controller; and
signal electronics joined to said power source, said controller and
said transducers, said controller further controlling said signal
electronics in response to data from said pressure sensor and said
salinity meter for driving said plurality of transducers.
8. The device according to claim 7 wherein: at least one of said
plurality of transducer elements receives acoustic signals from
said environmental fluid and transmits said received acoustic
signals to said signal electronics; and said signal electronics
transmit characteristics of said received acoustic signals to said
controller.
9. The device according to claim 7 wherein said sealing plug is
shaped to conform to the opening of the exterior wall.
10. The device according to claim 9 wherein said sealing plug
comprises: a plug portion slidably positioned in said sealed
housing opening; and a sealing washer positioned around the
perimeter of the plug portion between said plug portion and said
sealed housing.
11. The device according to claim 7 wherein said actuator mechanism
comprises: a linear actuator joined to said controller; a shaft
joined between said linear actuator and said sealing plug; and a
bracket fixed to an inner surface of said sealed housing supporting
said actuator mechanism.
12. The device according to claim 7 wherein said actuator mechanism
comprises: a motor joined to said controller; a drive gear
connected to and rotated by said motor; a power screw having thread
portions engaged with said drive gear at a first end thereof and
connected to said sealing plug at an opposing end thereof; and a
bracket fixed to an inner surface of said sealed housing supporting
said motor.
13. The device according to claim 12 wherein: said sealing plug has
a cavity formed within said sealing plug and an opening formed in a
surface of said sealing plug in communication with said cavity;
said power screw further including a plate member fixed to said
power screw opposing end, said plate member being positioned within
said sealing plug cavity, said plate member contacting said sealing
plug for moving said sealing plug.
Description
CROSS REFERENCE TO OTHER PATENT APPLICATIONS
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] (1) Field of the Invention
[0004] This invention generally relates to a self adjusting neutral
buoyancy countermeasure and system for underwater devices.
[0005] More particularly, the invention relates to a self adjusting
neutral buoyancy mechanism which effects slight changes in an
overall displacement of an underwater body, and thereby adjusts a
buoyancy force of the body.
[0006] (2) Description of the Prior Art
[0007] The current art for devices required to maintain certain
depths is known. These include military devices such as torpedo
countermeasures and oceanographic survey devices. Acoustic
countermeasures are particularly utilized to confuse hostile sonar
systems and protect existing force assets. Typical countermeasures
are launched from a submarine platform and use an active system to
traverse to a predetermined depth, maintain a hovering depth, and
begin operation. The known military devices utilize a propeller
system or a variable pressure gasbag system to maintain a
predetermined depth; however, these systems require active
manipulation to maintain their position. In general the devices
themselves are slightly negatively buoyant, thus requiring a means
of providing additional upward force to maintain depth and prevent
the device from free-falling to the ocean bottom.
[0008] A propeller system for an acoustic countermeasure device 10
is shown by way of example in FIG. 1. In the case of FIG. 1,
constant power is used to maintain the thrust that holds the device
10 at a predetermined depth D. The device 10 is comprised of a body
tube 12 which houses power and electronics, a transducer section 14
which produces the acoustic power, and a hovering system 16 which
provides thrust and keeps the device at the prescribed depth D in
the underwater environment 18. Thus, a problem exists in the art
whereby the space and energy requirements for deploying and
maintaining depth of one or more underwater devices, such as an
acoustic countermeasure device, should be minimized.
[0009] This invention describes a countermeasure as a single device
and as a system which encompasses the traditional acoustic traits
of countermeasures along with a novel hovering system and the use
of multiple numbers of these countermeasure devices simultaneously.
The invention disclosed here is designed to work on a body that is
essentially neutrally buoyant by design, and requires only slight
changes to effect depth control. Further, the invention herein
utilizes a more passive device for maintaining a predetermined
depth which takes less volume, weight and power than traditional
methods. The savings in weight, volume and power should allow for a
device design that is essentially neutrally buoyant on its own,
thus requiring only small changes in buoyancy to effect depth
change.
[0010] The following patents, for example, disclose various types
of depth adjusting devices, but do not disclose a novel hovering
mechanism allowing a submerged device to adjust and to maintain a
desired depth as does the present invention.
[0011] U.S. Pat. No. 2,790,186 to Carapellotti;
[0012] U.S. Pat. No. 4,286,539 to Pignone; and
[0013] U.S. Pat. No. 4,364,325 to Bowditch.
[0014] Specifically, Carapellotti discloses a buoy having an upper
enclosed chamber housing a weight therein and a lower chamber
joined to the upper chamber. The lower chamber has an open end
remote from the upper chamber and a weight therein adapted to pass
through the opening. A first removable closure member and a second
closure member are provided for the opening, the second closure
member being disposed in the lower chamber above the weight.
Flexible means connect the weight and the second closure member,
and orifices are provided in the lower chamber near the top
thereof. When the first closure member is removed from the opening
and the buoy is floated, the weight will pass through the opening
and be suspended beneath the buoy by the flexible means, the second
closure member will lodge on and seal the opening, and the lower
chamber will become substantially filled with water.
[0015] The patent to Pignone discloses a dual buoyancy device
having two external dimensions, in the smaller of which, one end is
closed by an elastic sheet undistended, and in the greater of which
the sheet is distended from its normal position thereby increasing
the external dimension of the device. The distention of the sheet
is accomplished by a thruster member bearing on the sheet which
thruster is impelled by a weight and lever system actuated by
gravity, which causes the thruster to distend the sheet. When the
sheet is distended, the overall volume increases causing the device
to float. When the sheet is undistended, the overall volume
decreases causing the device to sink. Distension of the sheet via
the thruster only occurs when the device is inverted. Still
further, there is no neutral buoyancy capability. The device either
sinks or floats.
[0016] Bowditch discloses a passive near neutral buoyancy platform
including a structure housing a series of gas-filled cells,
restrained in their maximum volume regardless of the internal
charge pressure, and collapsible in character when external
pressure exceeds the charge pressure. With this structure, once a
cell having a predetermined initial internal charge pressure
reaches a depth where the external pressure exceeds this initial
value, that cell contracts, resulting in a net buoyancy change for
the structure. Where this series of cells is attached integrally to
a single structure, the cells form a pre-loaded compressibility
compensation device matched to the external environment.
[0017] It should be understood that the present invention would in
fact enhance the functionality of the above patents by providing a
displacement mechanism for an underwater body in which the
displacement mechanism changes the total displacement of the body
and thereby a adjusts a buoyancy force of the body. This is done in
the present invention on a substantially neutrally buoyant device
and without the use of a known propeller system or a variable
pressure gas bag system.
SUMMARY OF THE INVENTION
[0018] Therefore it is an object of this invention to provide a
self adjusting neutral buoyancy device.
[0019] Another object of this invention is to provide a self
adjusting neutral buoyancy device deployed as a system of
devices.
[0020] Still another object of this invention is to provide a self
adjusting neutral buoyancy device having a mechanism for changing a
sealed volume of the device and thereby adjusting a depth at which
neutral buoyancy occurs.
[0021] A still further object of the invention is to provide a self
adjusting neutral buoyancy device which may be incorporated into
any underwater neutrally buoyant device.
[0022] Yet another object of this invention is to provide a self
adjusting neutral buoyancy device which is less costly and requires
less space than known devices.
[0023] In accordance with one aspect of this invention, there is
provided an underwater self adjusting displacement device including
a sealed housing having an exterior wall and an inner component
area, the exterior wall having an opening formed therein. A sealing
plug is slidably seated in the opening of the exterior wall, and an
actuator mechanism selectively adjusts the sealing plug within the
opening, thereby adjusting a total displacement of the sealed
housing. The displacement device is incorporated into any
substantially neutrally buoyant underwater deployable device such
as an acoustic countermeasure device or an oceanographic sensor
device. Further, the deployable devices may be deployed
individually or as a field. The displacement device requires less
weight and weight within an overall deployed device, enabling large
deployments and performance enhancements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The appended claims particularly point out and distinctly
claim the subject matter of this invention. 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:
[0025] FIG. 1 is a side view of an underwater acoustic
countermeasure device according to the Prior Art;
[0026] FIG. 2 is a side sectional view of a buoyancy displacement
device according to a preferred embodiment of the present
invention;
[0027] FIG. 3 is a side sectional view of a buoyancy displacement
device according to a further preferred embodiment of the present
invention;
[0028] FIG. 4 is a side sectional view of a generic underwater
device for use with the preferred embodiments of the present
invention;
[0029] FIG. 5 is a side sectional view of an acoustic
countermeasure device for use with the preferred embodiments of the
present invention; and
[0030] FIG. 6 is a side view of a field of countermeasure devices
deployed simultaneously according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] In general, the present invention is directed to a mechanism
which allows for a submerged device to adjust and maintain a
certain depth. Examples of devices which are required to remain
submerged at specific depths include military devices such as
torpedo countermeasures and oceanographic devices which float
submerged for long periods of time and map ocean currents. This
invention accomplishes a volumetric displacement change in a
submerged body which can alter and maintain floating at a certain
depth.
[0032] The invention is a mechanism to adjust and maintain depth
for a submerged underwater device. It is designed to operate on a
device which is essentially neutrally buoyant and requires only
slight changes in its displacement/buoyancy to effect depth
control. The variable density of seawater due to pressure as depth
increases allows for bodies to float at a constant depth beneath
the surface. Slight changes in the body's overall displacement can
affect its buoyancy, and thereby its depth. This mechanism allows
for changing the total displacement of a body and thereby an
adjustment in buoyancy force.
[0033] Turning now to FIG. 2, a first preferred embodiment of a
displacement device 20 is shown. It will be understood from the
following that the described displacement device 20 is applicable
to a number of end uses such as the acoustic countermeasure device
or oceanographic devices which float submerged for long periods of
time and map ocean currents. These end uses are mentioned by way of
example only and are not intended to limit the end uses of the
present invention.
[0034] The displacement device 20 includes a shell or body portion
22, the body portion 22 being closed and sealed to provide a
displacement of seawater and resulting buoyancy force. The body
portion 22 has an outer surface 24 in contact with the sea water,
and an inner wall surface 25 defining an inner chamber 26 for
housing components of the displacement device 20. An opening 28 is
formed through the body portion 22, the opening being defined by an
inner wall surface 30. A displacement mechanism 32 is provided in
connection with and sealed against the opening 28 of the body
portion 22. The displacement mechanism 32 is sealed with the
opening 28 so as to preserve the watertight integrity of the
displacement device 20 as will be further described in the
following.
[0035] The displacement mechanism 32 particularly includes a plug
member 34 having an outer peripheral shape corresponding to the
shape of the inner wall surface 30. The plug member 34 is sealed
against the wall surface 30 with an O-ring seal 36 therearound.
This seal 36 slides with the plug 34 to create a change in the
overall displacement of the underwater device 20.
[0036] This sliding motion of the plug 34 and seal 36 is created by
a linear actuator 38 mounted to the inner surface 25 of the body
portion 22 by a bracket 40 and bolts 42. An actuator shaft 44 is
interconnected between the actuator 38 and the plug 34 and allows
for controllable motion to be imparted from the actuator 38 to the
plug 34. The bracket 40 is shown as having a flange 40b extending
radially from a central shaft type housing 40a. The flange 40b is
flush with the inner surface 25 of the body 22 adjacent the opening
28. Although the bracket 40 having the housing 40a and flange 40b
is illustrated, it should be appreciated that the bracket 40 may be
of any suitable shape and attached in any known manner to the inner
surface 25 of the body portion 22 of the device. Further, although
the displacement device 20 is shown to utilize cylindrical parts
for the plug 34 and the opening 28, these shapes are not intended
to limit the invention.
[0037] Turning now to FIG. 3, an alternative displacement mechanism
46 is shown as another preferred embodiment. Like reference numbers
refer to like parts throughout this specification. Accordingly, the
body portion 22 having an opening 28 with an inner wall surface 30
formed therein remains the same as in FIG. 2. A displacement plug
48 is located concentrically within the opening 28 of the body 22
and includes an O-ring seal 50 formed therearound. The displacement
plug 48 is formed to include an opening 52 on an inner surface
thereof, the opening terminating in a cavity 54 within the plug 48
as shown.
[0038] The displacement plug 48 along with its seal 50 slides
within the wall surface 30 of the body portion 22 to create a
change in the overall displacement of the underwater device 20.
This sliding motion of the plug 48 and seal 50 is created by a
motor 56, a drive gear 58, and a power screw 60 engaged with drive
gear 58. The motor 56 is connected to the drive gear 58 with an
intermediary shaft 62. The power screw 60 includes an elongated
shaft portion 60a having gear threads 60b at one end thereof and a
plate 60c attached to the other end thereof. The plate portion 60c
is seated within the cavity 54 of the displacement plug 48 such
that the displacement plug 48 moves in response to movement of the
plate portion 60c. Rotation of the drive gear 58 translates to
linear movement of the power screw 60 by engagement of the drive
gear 58 with the threads 60b of the power screw 60. Power screw 60
and plate portion 60c can rotate when moved by drive gear 58
without requiring rotation of plug 48 and seal 50. These
incremental linear movements of the power screw 60 generate a
corresponding motion of the plug 48 and seal 50. Other means of
achieving the translation of the seal plug 48, such as by use of a
worm gear and rack or the like, may be affected by one of ordinary
skill in the art and is intended to be included within the scope of
the invention.
[0039] Similar to the embodiment of FIG. 2, the assembly is fixed
to the inner surface of the body 22 with a bracket 64, 66 and bolts
68. The bracket assembly includes a substantially vertical bracket
portion 64 and a substantially horizontal bracket portion 66. The
vertical bracket portion 64 supports the motor 56 of the
displacement mechanism and the horizontal bracket portion 66 is
flush with the inner surface 25 of the body for mounting thereto
with the bolts 68. At least a portion of the horizontal bracket 66
extends as an inner flange 66a to cover the opening 28 of the body
portion 22, such that the power screw 60 fits through an opening
66c thereof as shown. An outer flange portion 66b of the horizontal
bracket 66 is used to attach the bracket to the inner surface 25 of
the shell 22.
[0040] Adjustments of the plug 48 position in the opening 28 of the
shell 22 changes the overall buoyancy of the device 20 since the
displacement changes while the overall weight of the device remains
constant.
[0041] With the invention as described in FIGS. 2 and 3, there is
achieved a controllable change in depth for an underwater floating
device 20 through a small change in buoyancy. This is done in a
manner to only consume very small quantities of energy to effect
the change. Also, once the depth is attained, no further changes to
the system are required to maintain near term depth and the system
becomes truly passive. For extended time durations, movement of the
device to water of different temperature or salinity may require
further active adjustments.
[0042] Referring now to FIG. 4, there is shown a generic underwater
device 70 having a shell type body portion 72 as described in
connection with FIGS. 2 and 3. The body portion 72 is assumed to be
closed and sealed, providing a displacement of seawater and
resulting buoyancy force. Positioned within the device 70 is a
displacement mechanism 74 such as that described in connection with
either of FIG. 2 or 3. The displacement mechanism 74 is sealed
against the shell 72 to preserve watertight integrity. Also located
within the shell body 72 are a pressure sensor 76, a salinity meter
78, and a controller 80. Other instrumentation such as
accelerometers or motion detectors can also be provided and joined
to controller 80. By using the inputs of the pressure sensor 76 as
a measure of depth and the salinity meter 78 as a measure of salt
content (which affects buoyancy) the controller 80 can monitor the
environmental variables and adjust the system through a commanded
position for the displacement mechanism 74.
[0043] The displacement mechanism 74 functions in the same manner
as described in either of FIG. 2 or 3. The system 70 utilizes
commercial components for depth pressure sensing and salinity
measurements. A control algorithm developed to relate pressure,
salinity, and position control of the displacement mechanism in
order to achieve and maintain a prescribed depth can be implemented
using a relatively simple control circuit. Power can be supplied
through a battery, and likely would be supplied by whatever power
source is energizing the device's other functions.
[0044] Referring next to FIG. 5, there is illustrated an acoustic
countermeasure device 82 utilizing a displacement mechanism 84
according to the present invention as described in either of FIG. 2
or 3.
[0045] The acoustic countermeasure 82 is utilized as a decoy and
jammer in undersea warfare. Acoustic signals are transmitted which
can confuse the sonar systems of hostile torpedoes and submarines.
Similar to the previous figures, the acoustic countermeasure device
82 includes a shell type body 86 having an opening 88 therein for
receiving the displacement mechanism 84. The shell body 86 includes
an interior chamber 90 for accommodating operating elements of the
device 82. As shown in the FIG. 5, transducers 92 are mounted on or
in the walls of the shell body 86 and produce the acoustic signals.
A battery power source 94 and signal electronics 96 are located
within the chamber 90 and provide the power and signals for driving
the transducers 92. These systems are similar to current acoustic
systems used in countermeasure devices.
[0046] Similar to that of FIG. 4, the acoustic countermeasure
device 82 includes a salinity meter 98 and a pressure sensor 100. A
controller 102 coordinates the information gathered from the
salinity meter 98 and pressure sensor 100 in a manner identical to
that described above for FIG. 4. This system incorporates the
traditional acoustic transducers and electronics which supply the
sound into the water which is the product of an acoustic
countermeasure. The details will be eliminated herein for
brevity.
[0047] Referring now to FIG. 6, a field of acoustic countermeasure
devices 82 is shown to be deployed as a substantially simultaneous
event. Due to the volume saved by the novel buoyancy system, it is
anticipated that multiple countermeasure devices can be launched
using the volume previously required for a single device. As such,
the application of simultaneously dispersed fields of
countermeasures becomes an available option. These countermeasures
can all be set to hover at different depths (D1, D2, D3).
Additionally, delays in launching while the launch platform is in
motion will provide spatial separations (S1, S2). The net effect is
a series of acoustic sources at different depths and locations.
This can cause a threat weapon or platform to rule out multiple
sources as decoys rather than one. If the countermeasures 82 are
employing different frequency bands in their transmissions,
additional processing problems for the threat assets arise.
[0048] Incorporated into each of the countermeasures 82 of FIG. 6
is the novel displacement mechanism of FIG. 2 or 3 to achieve and
maintain a prescribed depth of the individual countermeasures which
together make up the system. The variable density of seawater due
to pressure as depth increases and changes in temperature allows
for bodies to float at a constant depth beneath the surface. Slight
changes in the body's overall displacement can affect its buoyancy,
and thereby its depth. This system allows for changing the total
displacement of a body and thereby an adjustment in buoyancy force
to achieve and maintain a desired depth by an underwater
device.
[0049] The arrangement of FIG. 6 is advantageous in that it
provides a multiple acoustic countermeasure system which presents
multiple acoustic sources/frequencies to confuse incoming
threats.
[0050] Through an acoustic countermeasure system as described, the
overall device may be made smaller than traditional devices due to
the weight, volume, and power savings afforded by the novel depth
control system. This may make available the option to package two
devices into the launch apparatus currently used to deploy one
device.
[0051] The exact number of countermeasures used in the multiple
countermeasure system can vary. The number available and mission
specifics will affect launch numbers and individual depth/frequency
assignments.
[0052] The tolerance for depth accuracy and the time duration of
the device mission can alter the control system components. If a
short duration mission is required, and the area of the ocean
known, then the need to measure and monitor salinity is reduced and
this aspect of the control system could be omitted. Further, the
specific mission of the countermeasure will influence the choice of
transducers and the requisite power levels.
[0053] In view of the above detailed description, it is anticipated
that the invention herein will have far reaching applications other
than those of underwater systems such as acoustic countermeasures
and oceanographic devices.
[0054] 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.
* * * * *