Ammunition and explosives – Projectiles – Line carrying or filamentary material distributing
Reexamination Certificate
2001-02-23
2002-12-31
Carone, Michael J. (Department: 3641)
Ammunition and explosives
Projectiles
Line carrying or filamentary material distributing
C102S502000, C102S503000, C102S504000, C089S001540
Reexamination Certificate
active
06499407
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
(Not Applicable)
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
(Not Applicable)
BACKGROUND OF THE INVENTION
The present invention relates generally to expendable decoys, and more particularly to a method for packaging infrared decoy foils within a canister which allows for controlled dispensing and dispersal of the foils. The infrared foils are typically a Special Material (SM) which, when brought into contact with air, become warm and radiate infrared energy.
As is well known in the prior art, military aircraft are typically provided with decoys which are used to draw various types of guided weapons away from the aircraft. One of the most commonly used decoy devices is a flare which is adapted to attract infrared or heat seeking guided missiles away from the deploying aircraft. In this respect, the flare is designed to present a larger thermal target than the aircraft from which it is deployed, thus attracting the weapon away from the aircraft.
Over recent years, flares have become decreasingly effective as decoy devices due to anti-aircraft weaponry having become more sophisticated and provided with enhanced capabilities to discriminate between flares and the deploying aircraft. In this respect, modern heat seeking missiles are typically provided with both a frequency discriminator which is adapted to sense the intensity of the infrared signature of the aircraft and a kinetic discriminator which is adapted to sense the speed and trajectory at which the infrared signature is traveling. When a conventional flare is deployed from the aircraft, the infrared signature produced thereby is typically more intense in the near visible frequency range than that produced by the engines of the aircraft, with the velocity and trajectory of the flare being significantly different than that of the deploying aircraft since the flare, once deployed, slows rapidly and falls straight toward the ground. The frequency discriminator of the guided missile is adapted to distinguish between the infrared signature produced by the flare and that produced by the engines of the aircraft. Additionally, the kinetic discriminator of the guided missile is adapted to distinguish between the velocity and trajectory of the aircraft and that of the flare, even if the frequency discriminator does not distinguish the infrared signatures produced thereby. As such, the combined functionality of the frequency and kinetic discriminators of the guided missile typically succeeds in causing the guided missile to disregard the deployed flare, and continue to target the aircraft.
In addition, the principal problem associated with current decoy systems is that an aircraft can only carry a limited number of them. There are not enough to allow for continuous dispensing of decoys. Therefore, the aircraft must be equipped with detectors that warn of a missile's approach such that decoys may be dispensed. With the missile flight time very short, there is insufficient time to react in all situations. Further, such missile warning detectors are not always reliable.
In view of the above-described shortcomings of conventional flares, there exists a need in the art for a system which is adapted to create an infrared signature which is similar in magnitude or intensity to that produced by aircraft engines, appears to travel at a velocity and trajectory commensurate to that of the aircraft, and can provide continuous protection while the aircraft is over threat territory.
Prior art has developed methods of dispensing limited amounts of SM foils from aircraft. This has been done by means of stacking SM foils in a canister and ejecting them all at once using an explosive charge. The principle disadvantage of such an approach is that it provides only momentary protection since it produces one intense cloud, which does not follow the aircraft.
A preferred method is to deploy the SM foils in small packets or continuously from a canister using a drive screw or similar device. This has been accomplished successfully for relatively short stacks of SM foils by means of a piston driven by a lead screw. It has also been accomplished by packaging the SM foils into small packets, which engage a drive belt that drives them out of the canister. These methods dispense the SM foils approximately continuously such that the infrared cloud produced thereby appears to match the aircraft kinematics. They are capable of dispensing over a longer time period offering many seconds of continuous protection.
In order to provide protection for an extended period of time, it is desirable to package the SM foils into canisters which are much longer. While this can be accomplished by means of engaging individual packets of SM foils to a drive belt as described above, the method is more mechanically complex, less volume efficient and allows less flexibility in how the SM foils are dispensed than does a canister with a piston/lead screw.
Using prior art methods, problems are encountered by deploying long columns of SM foils from a piston/lead screw canister. Such canisters are typically comprised of a hollow tube with a piston at one end, and spring fingers at the other. The SM foil stack is located between the piston and spring fingers. The purpose of the spring fingers is to retain the SM foils until such time as they are forced out of the canister by the piston. The stack of SM foils has a great deal of compliance. Since none of the foils are perfectly flat, the column acts as a long spring. As the piston drives the SM foils out, the SM stack compresses against the spring fingers until they are finally let go, at which time a large slug of the SM foils is dispensed. This effect is minimal for short stacks of SM foils but prevents controlled and uniform dispensing of long stacks of SM foils.
The present invention will describe a method and related apparatus for packaging SM foils into long canisters that will allow for controlled and even dispensing therefrom.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a decoy pod comprising at least one elongate, tubular canister which defines a forward end and an aft end. The canister preferably has a generally square cross-sectional configuration, and defines a canister axis. Extending within the canister along the canister axis is an elongate, rotatable drive screw which includes a drive screw thread and defines a root diameter. Threadably engaged to the drive screw is a piston which is disposed adjacent the forward end of the canister. The threadable engagement between the drive screw and the piston is such that the rotation of the drive screw will facilitate the movement of the piston along the canister axis toward the aft end of the canister.
The decoy pod further comprises multiple stacks of SM decoy foils which are disposed within the canister. The decoy foils each have a generally square configuration, and are each provided with a pre-cut clearance hole within the approximate center thereof. Each stack of the decoy foils is preferably formed to have a height in the range of from about 0.5 inches to about 8.0 inches, and most preferably in the range of from about 1.0 inches to about 3.0 inches. The hole within each decoy foil is sized to allow the drive screw to easily pass therethrough.
The decoy pod of the present invention further comprises multiple separator plates which are each cooperatively engaged to the drive screw and disposed between an adjacent pair of the stacks of the decoy foils loaded into the canister. The separator plates are operative to apply a preload to respective ones of the stacks. In this respect, after each stack of the decoy foils is loaded into the interior of the canister, a separator plate is installed on top of the just loaded stack. The separator plates each have approximately the same form as the decoy foils, i.e., a thin, generally square configuration. Additionally, each of the separator plates is formed to include at least one hole in the approximate center thereof which is sized and conf
Carone Michael J.
Meggitt Defense Systems
Stetina Brunda Garred & Brucker
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