This case is related to the following U.S. patent application Ser. Nos.: 12/165,066 (Underwater Gun Comprising a Barrel-Adapter including a Barrel Seal), 12/165,079 (Underwater Gun Comprising a Plate-Type Barrel Seal), 12/165,079 (Underwater Gun Comprising a Passive Fluidic Barrel Seal), and 12/165,090 (Underwater Gun Comprising a Turbine-Based Barrel Seal), all of which were filed on even date herewith and all of which are incorporated by reference herein.
The present invention relates to underwater guns.
Underwater guns are useful as anti-mine and anti-torpedo devices. Recently, autonomous underwater vehicles (AUVs) have been fitted with underwater guns for torpedo defense and underwater “hunter-killer” CONOPs.
A gun, especially one with a high muzzle velocity, cannot be fired when water is in its barrel. If a firing where to incur in a water-filled barrel, a very high breach pressure would result as the ignited propellant charge forces (or tries to force) the water out of the barrel. The likely result would be material failure of the barrel.
The prior art is replete with approaches for waterproofing the barrel of an underwater gun, or for clearing water from its barrel before firing. U.S. Pat. No. 5,639,982 discloses a means for firing a fully automatic gun underwater using a blank barrel-clearance round. Blank barrel-clearance rounds are alternated with live rounds of ammunition. To begin the process, a blank barrel-clearance round is first detonated. This creates gas and steam within the chamber that forms a bubble at the muzzle end of the barrel, thereby displacing water from the chamber. A live round is then immediately fired. The process is repeated, whereby the subsequent detonation of a blank barrel-clearance round displaces any water that has re-entered the barrel subsequent to the firing of the live round.
U.S. Pat. No. 5,648,631 discloses a spooled tape seal for sealing the barrel of an underwater gun. The system includes a tap that covers the opening of the gun barrel and sprockets for advancing the tape across the opening. Hydrostatic pressure keeps the tape pressed to the end of the barrel to create an effective seal. When a bullet is fired, it perforates the tape. During this brief period of egress, the exhaust gases from combustion of the propellant charge keep water from entering the barrel. Almost immediately, a non-perforated portion of the tape is advanced by the sprockets to cover the barrel opening. External hydrostatic pressure re-seats the tape, thereby preventing water from entering the barrel.
U.S. Pat. No. 5,687,501 discloses a sealing plate for providing a watertight seal for a multi- or single-barreled underwater gun. The sealing plate provides one or more firing apertures in an otherwise solid surface. Between firings, the gun muzzle is sealed by a solid surface of the sealing plate. To fire a bullet, the sealing plate or muzzle rotates to align the gun muzzle with one of the firing apertures. This permits unimpeded egress. After the bullet fires, the plate or muzzle again rotates so that a solid portion of the sealing plate covers the muzzle.
These are but a few of the many patents pertaining to various aspects of underwater gun design in general, and to the water-in-the-barrel problem, in particular. Not with standing the many approaches to the problem, no truly satisfactory approach has been developed for keeping water out of the barrel of an underwater gun between and during operation.
The present invention provides an underwater gun having a barrel seal for preventing water from entering the barrel between the firing of rounds.
In the illustrative embodiment, the barrel seal is a valve that is disposed in the barrel of a gun. The valve is operatively coupled to a valve actuator. The valve actuator is operable to open or close the valve, thereby unsealing or sealing the barrel.
In accordance with the invention, the valve can be any of a variety of different types of valves, including, without limitation, a gate valve, a ball valve, and an iris valve. Furthermore, the valve actuator can take any one of a variety of different forms, such as, without limitation, a cylinder and piston arrangement or a motor. In some embodiments, the valve actuator includes, as a function of valve type, an arrangement for converting linear motion (e.g., of a piston, etc.) to rotational motion (e.g., to rotate the valve, etc.).
In various embodiments, the valve actuator is driven via different forms of power. For example, in some embodiments in which the valve actuator comprises a cylinder and piston, the valve actuator is driven by the combustion gases that are generated as the round's chemical propellant is ignited during firing. In some other embodiments, the valve actuator is driven by electricity or hydraulics, among other forms of power.
The terms appearing below are defined for use in this specification, including the appended claims, as follows:
The present invention pertains to guns that are intended for (1) use in an underwater environment and (2) firing rounds that include a chemical propellant. The underwater guns described herein will typically, although not necessarily, be fitted to AUVs. For clarity, gun 100 is typically depicted in the Figures as having a single round in the chamber or bore. It is to be understood, however, that gun 100 is typically a multi-shot weapon.
Barrel 102, chamber 104, and bore 108 are conventional features of most guns. Fire-control system 110 is basically a computer and ancillary elements that enable gun 100 to hit a target. The relative sophistication of any particular embodiment of fire-control system 110 is primarily a function of the intended application for gun 100. That is, a relatively more sophisticated fire-control system is required for a relatively more autonomous application (e.g., for use in conjunction with an AUV, etc.).
In a typical embodiment, fire-control system 110 interfaces with one or more sensors (e.g., sonar, radar, infra-red search and track, laser range-finders, water current, thermometers, etc.). The sensor input is used to develop a firing solution for a target. To the extent that gun 100 is located on an AUV, etc., fire-control system 110 advantageously takes into account movements of the AUV itself. And, when associated with an AUV, fire-control system 110 is operatively coupled to aiming and firing mechanisms.
The fire-control system is not particularly germane to an understanding of the invention and, furthermore, is well understood by those skilled in the art. As a consequence, fire-control system 110 will not be described in further detail.
Valve 114, which in the illustrative embodiment is disposed at the muzzle end 106 of barrel 102, functions as a barrel seal for gun 100. Valve 114 has two primary states: one state in which the valve is “closed” and another state in which the valve is “open.” When valve 114 is closed, it prevents water from advancing into barrel 102. When valve 114 is open, it unseals barrel 102, thereby enabling round 112 to be fired.
Valve 114 is controlled (i.e., moved between the two states) by valve actuator 116. A variety of different actuation schemes can be used to actuate valve 114. The selection of a particular type of actuator is dependent, to some extent, upon the specifics of valve 114 (e.g., gate valve, ball valve, iris valve, etc.) and the form of the power being used to drive actuator 116 (e.g., electricity, gas, etc.).
In some embodiments, valve actuator 116 is operatively coupled to fire-control system 110. This might be required to time the opening of valve 114 with the firing of a round, as a function of the actuation system.
This specification now proceeds with a description of several embodiments of underwater gun 100. These embodiments are distinguished from one another by the specifics of valve 114 and/or valve actuator 116.
Gun 100 of
With reference to
Upon firing, some of the combustion gases are blown out of muzzle end 106 of bore 108. This has the effect of clearing any water that was residing in barrel 102 “downstream” of valve 214.
To the extent that gun 100 continues to fire rounds, the substantially continuous generation of combustion gases will support piston 226 such that valve 214 remains in its “open” state. As a consequence, bore 108 remains open to permit rounds to be fired from gun 100.
In some embodiments, cylinder 224 is closed to the ambient environment. In such embodiments, a spring or other device (not depicted) that is arranged to provide a restoring force is disposed within cylinder 224. The restoring force urges piston 226 back toward barrel 102. Once firing ceases, the pressure rapidly decreases in the region below piston 226 such that there will be insufficient pressure to overcome the restoring force that is provided by the spring, etc. As a consequence, piston 226 drops and valve 214 re-seats in barrel 102, thereby blocking bore 108.
In some other embodiments, cylinder 224 is open to the ambient environment. In such an embodiment, the ambient water pressure bearing on piston 226 provides the restoring force that would otherwise be provided by a spring or other mechanism in a closed cylinder.
In the embodiment of gun 100 that is depicted in
Notwithstanding the aforementioned “automatic” valve actuation, timing of the valve's movement is important. It can be readily determined how much time is required for a round to reach the location of the valve, how much force is available from combustion to operate the valve actuator, and how much force will be required to actuate the valve and cause it to open with the requisite speed. As a function of the chemical propellant used in the round, the weight of the piston, and other factors, in some embodiments, a separate charge (in addition to the round's chemical propellant) will be required to actuate valve 214.
In fact, it is possible that valve 214 must start to move before live round 112 is fired. In such cases, a separate charge will be required, and it will need to be pre-fired (before the live round), so that pressure can build to a sufficient extent to move the piston.
Another way to address the timing issue is to provide a round that exhibits a staggered acceleration profile. In particular, a round is provided with two or more separate charges of chemical propellant, the ignition of which is staged. As a consequence, the round is first accelerated, compresses gas in bore 108 and decelerates briefly until valve 214 fully withdraws (i.e., opens), and then is re-accelerated with the ignition of the second charge of propellant.
In the illustrative embodiment that is depicted in
Gun 100 of
Like the embodiment depicted in
Referring now to
As piston 226 advances through cylinder 224, pinion gear 430 is rotated via the movement of rack 428. In turn, ball valve 414 rotates from a closed state, as depicted in
Upon firing, some of the combustion gases are blown out of muzzle end 106 of bore 108. This clears any water that resides in barrel 102 “downstream” of valve 414.
A torsion spring (not depicted) that is operatively coupled to the ball valve 414 provides a restoring force to return piston 426 to its rest position at the “bottom” of cylinder 424. When round 112 is first fired, the increase in pressure due to the rapid generation of combustion gases overcomes the restoring force of the spring and causes piston 426 to move through cylinder 424. But as the combustion gases dissipate, the pressure drops, and piston 426 returns to its rest position.
To the extent that gun 100 continues to fire rounds, the substantially continuous generation of combustion gases will support piston 426 such that valve 414 remains in its “open” state. As a consequence, bore 108 remains open to permit rounds to be fired from gun 100.
Like the embodiment of gun 100 that is depicted in
But as described in conjunction with the embodiment depicted in
Furthermore, in some other embodiments of gun 100, other valve actuation arrangements known to those skilled in the art are suitably used, including, without limitation, a piston/cylinder arrangement that is hydraulically actuated, linkages that operably couple valve 414 to a motor, and the like. In these arrangements, valve actuation is not “automatic” in the sense previously described. As a consequence, in such embodiments, the actuation of valve 414 is responsive to information (e.g., a signal) from fire-control system 110. An example of an embodiment in which valve actuation is under the control of fire-control system 110 is described below in conjunction with
Gun 100 of
In the closed state, the iris valve seals barrel 102 against water intrusion. For the embodiment of gun 100 that is depicted in
Iris valve 614 is operatively coupled, via appropriate linkages (not depicted), to motor 634. The motor, typically an electrical motor, drives the opening and closing of iris valve 614. In the previous embodiments, valve actuation was “automatic” in the sense that it was driven by combustion gases. But for the embodiment depicted in
More particularly, fire-control system 110 sends a signal to controller 632 at an appropriate time as a function of valve response, etc., to actuate motor 634 to change the state of valve 614. With regard to timing, it is possible that due to the response of valve 614, the valve might need to begin opening before a round is fired. In such a case, after fire-control system 110 has a solution but before it sends a command to fire, it sends a signal to controller 632 to begin opening valve 614. Valve 614 also closes via the action of fire-control system 110.
In some other cases, the fire-control system 110 sends a signal to controller 632 that indicates that a round is about to be fired. The controller then actuates motor 634 to open valve 614 after a first delay, wherein the delay is based on the time it takes for a pressure wave from combustion gases to arrive at the valve. In the case of the firing of a single round, valve 614 closes after a second delay, wherein the second delay is based on the time it takes for the round to transit valve 614.
The operation of this embodiment is analogous to the operation of an underwater camera. In fact, in a further embodiment, an electronically-controlled shutter such as adapted from an underwater camera serves as the valve-based barrel seal. The shutter is simply activated by fire-control system 110.
It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims.
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Number | Date | Country | |
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20090320345 A1 | Dec 2009 | US |