Fin deployment system

Abstract

A projectile having a fin deployment system disposed about its circumference. The fins are initially contained by a fin cover that is removed by aerodynamic force. The fins are then rotated around a rotational axis parallel to and offset from the central axial axis of the projectile body by the centrifugal forces created by the rotation of the projectile as the projectile passes through a barrel of a gun system or tube launcher. The fin deployment system can also have locking systems that lock the fins in the deployed position and prevent the fins from rotating back into the retracted position after deployment.

Claims

1. A fin deployment system for a projectile comprising a plurality of fins rotatable along a rotational axis parallel to and offset from the central axial axis of a projectile body, wherein each fin is rotatable around the rotational axis between a retracted position and a deployed position, rotation to the deployed position occurs only from the centrifugal forces generated by the spinning of the projectile; a cylindrical mount assembly defining a plurality of axial channels each aligning with the offset rotational axis of a corresponding fin; said cylindrical mount assembly having a solid interior face for defining a central opening and wrapping around the circumference of the aft end of the projectile so that the cylindrical mount assembly remains independent of the projectile; a fin cover positioned over the fins and cylindrical mount assembly when the fins are positioned in the retracted position, and wherein the fin cover slidably engages the cylindrical mount so that as the projectile exits a tube or a gun barrel, aerodynamic drag separates the fin cover from the projectile; said fin cover having a tubular shape so as not to block the aft end of the projectile; and wherein said fin cover completely covers each fin to prevent rotation of the barrel within the axial channel until the fin cover is removed and the fin cover includes axial indentations on an outer face for placement of a vent to equalize the pressure between the fin cover and the cylindrical mount assembly during operation.

2. The fin deployment system of claim 1 wherein the offset rotational axis is proximate to the exterior of the projectile body such that each fin can be rotated into the retracted position, wherein the fin is generally aligned with or contoured to follow the exterior of the projectile body when positioned in the retracted position.

3. The fin deployment system of claim 1 wherein each fin comprises a fin portion and a barrel portion at one end of the fin portion and rotatable within the axial channel between the retracted position and the deployed position.

4. The fin deployment system of claim 3 wherein the fin deployment system can further comprise a locking ring defining a plurality of engagement surfaces corresponding to each of the axial channels.

5. The fin deployment system of claim 4 wherein each fin can comprise a drive axle extending through the barrel of the fin, wherein the locking ring defines a first plurality of ports each corresponding to one of the plurality of axial channels and adapted to rotatably receive one end of the drive axle.

6. The fin deployment system of claim 5 wherein the fin deployment assembly can further comprise a secondary ring positioned opposite the locking ring against an opposite end of the cylindrical mount assembly, said secondary ring defines a second plurality of ports each corresponding to one of the plurality of axial channels and adapted to rotatably receive the opposite end of the drive axle.

7. The fin deployment system of claim 3 wherein the barrel portion of the fin can comprise a protrusion or define a cutout that is rotated into engagement with a stop protrusion when the fin is rotated into the deployed position, said stop protrusion is positioned to engage the fin portion and stop the rotation of the fin when the fin portion is positioned in a plane transverse the central axis of the projectile, thereby preventing over rotation of the fin portion and maintaining a proper spacing of the deployed fins.

8. The fin deployment system of claim 3 wherein the barrel of each fin can define a cutout portion providing an engagable locking surface so that each axial channel defines a groove that aligns with the cutout portion when the barrel is rotated into the deployed position.

9. The fin deployment system of claim 8 wherein the cylindrical mount assembly further comprises a locking tab with a corresponding spring positioned within each groove so that upon rotation of the fin into the deployed position and the alignment of the cutout portion with the groove, the spring is biased to push the locking tab out of the groove such that locking tab at least partially protrudes from the groove and engages the locking surface to prevent the fin from rotating back to the retracted position.

10. The fin deployment system of claim 1 wherein the fin cover can comprise at least one vent for equalizing the pressure of any air contained within the fin cover with atmospheric pressure as the projectile leaves the barrel or tube launcher.

11. A projectile comprising a projectile body and a fin deployment system, said fin deployment system comprising; a plurality of fins; a cylindrical mount assembly having a tubular shape with an outer surface and an inner surface, the inner surface being a uniform face without need for openings or interaction with the projectile body, wherein each fin further comprises a fin portion and a barrel positioned at one end of the fin portion such that rotation of the barrel rotates the fin portion around the rotational axis of the barrel, the rotation of the fins created only by the centrifugal force of the rotating projectile; wherein the outer face of the cylindrical mount assembly defines a plurality of axial channels each corresponding to one of the fins and adapted to rotatably receive the barrel of the corresponding fin; and a fin cover positioned completely over the fins, said fin cover having a tubular shape and slidably engaging the cylindrical mount assembly, said fin cover separating from the fin deployment system due to aerodynamic forces experienced by the fin cover after launch from a gun barrel or tube; wherein said fin cover completely covers each fin to prevent rotation of the barrel within the axial channel until the fin cover is removed and the fin cover includes axial indentations on an outer face for placement of a vent to equalize the pressure between the fin cover and the cylindrical mount assembly during operation.

12. A method of deploying a plurality of fins from a tube or barrel launched projectile, the method comprising: mounting a cylindrical mount assembly about the circumference of the aft end of the projectile, said cylindrical mount assembly including a plurality of fins, wherein the fins are rotatable along a rotational axis offset from a projectile central axis, the cylindrical mount assembly including all the necessary structure for maintaining and rotating the fins to a deployed position so as not to require structure within the projectile; rotating the fins into a retracted position such that the fins are generally aligned tangential with the exterior of the projectile body; fitting a removable fin cover over the cylindrical mount assembly, said fin cover holding the plurality of fins in the retracted position, wherein said fin cover completely covers each fin to prevent rotation of the barrel within the axial channel until the fin cover is removed and the fin cover includes axial indentations on an outer face for placement of a vent to equalize the pressure between the fin cover and the cylindrical mount assembly during operation; firing the projectile from a tube or barrel, wherein the barrel or tube rotates the projectile body around the central axis; removing the fin cover after the projectile leaves the tube or barrel by aerodynamic forces experienced by the fin cover after launch from the tube or barrel; and deploying the fins by the rotation of the projectile.

13. The method of deploying a plurality of fins according to claim 12 further including locking the fins in a deployed position, wherein said deployed position is generally in a plane transverse the central axis of the projectile, said cylindrical mount assembly comprising the locking mechanism.

14. The method of deploying a plurality of fins according to claim 12 wherein aerodynamic drag separates the fin cover from the projectile.

15. The method of deploying a plurality of fins according to claim 12 wherein the fin cover includes at least one vent for equalizing the pressure of any air contained within the fin cover with atmospheric pressure as the projectile leaves the barrel or tube launcher.

16. The method of deploying a plurality of fins according to claim 12 wherein each fin comprises a fin portion and a barrel portion at one end of the fin portion and said fin rotatable between the retracted position and the deployed position.

17. The method of deploying a plurality of fins according to claim 16 wherein the rotation of the projectile imparted by the rifling of the barrel or tube creates centrifugal forces causing the barrel of each fin to rotate the fin portion until the fin portion extends axially outward from the central rotational axis of the projectile upon exiting the muzzle of the barrel.

18. The method of deploying a plurality of fins according to claim 12 further including rotating the projectile body by an air scoop shaped to create axial rotation of the projectile.

19. The method of deploying a plurality of fins according to claim 12 further including rotating the projectile body by angling a rocket exhaust, said rocket exhaust provided by a rocket disposed within the projectile body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention can be completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:

(2) FIG. 1 is a perspective view of a projectile, according to an embodiment of the present invention, prior to fin deployment.

(3) FIG. 2 is an exploded perspective view of a projectile according to an embodiment of the present invention.

(4) FIG. 3 is a perspective view of a projectile, according to an embodiment of the present invention, after fin deployment.

(5) FIG. 4 is an exploded perspective view of a fin cover and a fin deployment system, according to an embodiment of the present invention, prior to fin deployment.

(6) FIG. 5 is a perspective view of a fin cover and a fin deployment system assembly, according to an embodiment of the present invention, prior to fin deployment.

(7) FIG. 6 is a perspective view of a fin deployment system after fin deployment according to an embodiment of the present invention.

(8) FIG. 7 is a partial cross-sectional view of a fin deployment system prior to fixation of the fins in the deployed position.

(9) FIG. 8 is a partial cross-sectional view of a fin deployment system after fixation of the fins in the deployed position.

(10) While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. 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

(11) As depicted in FIGS. 1 and 3, a projectile 20, according to an embodiment of the present invention, comprises a projectile body 22 and a fin deployment system 24. The projectile body 22 further comprises an ogive tip portion 26 and a cylindrical end portion 28. The projectile body 22 defines a central axial axis extending between the tip portion 26 and the cylindrical end portion 28 and intersecting the tip of the tip portion 26. In one aspect, the cylindrical end portion 28 is sized to engage the barrel walls or the walls of the tube launcher to align the projectile 20 with the central axis of the barrel or tube launcher. In one aspect, the projectile body 22 can define an internal cavity for receiving ordinance and other payloads. As depicted in FIGS. 1 and 3, the fin deployment system 24 is positioned at the rear of the projectile body 22 against the cylindrical end portion 28.

(12) As depicted in FIGS. 1-3, the fin deployment system 24 comprises a plurality of fins 30 and a cylindrical mount assembly 32. Each fin 30 further comprises a fin portion 34 and a barrel 36 positioned at one end of the fin portion 34 such that the barrel 36 can be rotated to rotate the fin portion 34 around the barrel 36. While fins 30 are depicted as flat in the attached drawings, it is envisioned that fins 30 may have a curvature to more closely fit the outer circumference of the projectile, or may be shaped with varying thickness depending upon expected flight dynamics. In one aspect, the fin portion 34 can comprise a cutout portion 35 angled to facilitate rotation of the projectile 20 in flight to facilitate continued rotation of the projectile 20 in flight after leaving the barrel or tube. The cylindrical mount assembly 32 similarly defines a plurality of axial channels 38 each corresponding to one of the plurality of fins 30 and adapted to rotatably receive the barrel 36 of each fin 30. Each channel 38 provides a bearing surface for allowing the barrel 36 for rotating within the channel 38 to move the fin portion 34 between the retracted and deployed positions. The channel 38 defines a rotational axis for barrel 36 that is parallel to, but offset from the central axial axis. In one aspect, the cylindrical mount assembly 32 defines an internal space that can be used to receive a rocket motor, additional ordinance or other payloads.

(13) As depicted in FIGS. 2-4 and 6-8, each barrel 36 is rotatable to move the fin portion 34 between a retracted position and a deployed position. In the retracted position, the fin portion 34 is generally aligned with the exterior of the cylindrical end portion 28 such that plurality of fins 30 are arranged around the interior space defined by the mount assembly 32 when in the retracted position. In one aspect, the fins 30 are sized such that the tip of each fin portion 34 is proximate to the barrel 36 of the next fin 30 and no portion of the fin portion 34 protrudes past the outer diameter defined by the projectile body 22. In this configuration, the cylindrical end portion 28 provides the primary engagement between the projectile 20 and the barrel or tube that aligns the central axis of the projectile body 22 with the central axis of the barrel or tube. In the deployed position, each fin portion 34 is positioned within a plane transverse to the central axis of the projectile body 22. Similarly, a portion of the fin portion 34 extends beyond the outer diameter of the projectile body 22 to better engage the air in flight.

(14) The rotation of the fin portions 34 between the retracted position and the deployed position is facilitated by the centrifugal force created by the rotation projectile 20 as the projectile 20 leaves the barrel or tube. The rotation can be facilitated by the barrel rifling, shaped air scoops in the tip 26, angling of the starter motor nozzles and other conventional means of imparting spin to the projectile 20 as the projectile 20 travels through the barrel or tube. Unlike conventional fin deployment systems, the present fin deployment system 24 deploys the fins 30 without any mechanical assembly, such as a spring or lever, and relies on the natural or created rotation of the projectile 20 to deploy the fins 30, thereby reducing the risk that fins 30 will fail to deploy due to mechanical failure or damage.

(15) As depicted in FIGS. 4-5, in one aspect, the fin deployment system 24 can further comprise a fin cover 40 positionable over the fins 30 and the mount assembly 32. The fin cover 40 further comprises plurality of indented portions 42 that engage the fin portions 34 to maintain the fin portions 34 in the retracted position as the projectile 20 travels through the barrel or tube. The fin cover 40 separates from the fins 30 and the mount assembly 32 as the projectile 20 exits the barrel or tube allowing the fins 30 to rotate into the deployed positions. In one aspect, the fin cover 40 is retained by a friction fit such that the drag caused by the air as the projectile 20 leaves the barrel or tube overcomes the friction fit and separates the fin cover 40 from the projectile 20. In one aspect, a portion of the fin deployment system 24 can engage the barrel or tube to assist the projectile body 24 in maintaining the alignment of the projectile 20 to the barrel or tube. In one aspect, the fin cover 40 can comprise a plurality of vents 74 that equalize the air pressure within the fin cover 40 with the surrounding air pressure to avoid formation of high pressure air pockets beneath the fin cover 40. As depicted in FIGS. 4-5, the vents 74 can be positioned within the indented portions 42 to prevent the edges of the vent 74 from engaging the rifling of the barrel or otherwise impacting the flight of the projectile.

(16) As depicted in FIGS. 7-8, in one aspect, the fin deployment system 24 can further comprise a locking ring 44 affixed to an end of the mount assembly 32. The locking ring 44 defines a plurality of engagement surfaces 46 each corresponding to one of the axial channels 38 and positioned to engage the fin portion 34 as the fin portion 34 is rotated into the deployed position. In this configuration, each barrel 36 comprises at least one stop protrusion 47 that engages the engagement surfaces 46 to prevent the fin portion 34 from over-rotating past the deployed position. In one aspect, the locking ring 44 can define a plurality of ports 48 for receiving a plurality of fasteners 50 for securing the locking ring 44 to the mount assembly 32.

(17) As depicted in FIGS. 7-8, in one aspect, each barrel 36 can define a cutout portion providing a locking surface on the barrel 36. In this configuration, the mount assembly 32 defines a groove 50 that aligns with the locking surface of the barrel 36 when the fin portion 34 is positioned in the extended position. The mount assembly 32 further comprises a locking tab 52 and a flat spring 54 positioned within the groove 50. The flat spring 54 biases the locking tab 52 against the barrel 36. The barrel 36 retains the locking tab 52 within the groove 50 until the engagement surface aligns with the groove 50 at which point the locking tab 52 is free to be pushed by the spring 54 from the groove 50. The locking tab 50 engages the engagement surface to prevent the rotation of the fin portion 34 back to the retracted position after the fin portion 34 is rotated into the extended position. The locking tab 50 and the stop protrusion 46 to maintain the fin portion 34 in the deployed position.

(18) As depicted in FIG. 2, in one aspect, each fin 30 further comprises a drive axle 56 extending axially through the barrel 36. The barrel 36 can further comprise at least one loop 58 for receiving the drive axle 56. As depicted in FIG. 2, each fin 30 comprises two drive axles 56 each extending from one end of the barrel 36. In this configuration, the locking ring 44 defines a first plurality of ports 60 for rotatably receiving one end of the drive axle 56. In one aspect, the locking ring 44 can further comprise a plurality of fasteners 57 for securing the end of the drive axle 56 within the first plurality of ports 60. In one aspect, the mount assembly 32 further comprises a flared portion 62 defining a plurality of second plurality of ports 62 for rotatably receiving the opposite end of the drive axle 56. The first and second plurality of ports 60, 64 cooperate to maintain the barrel 36 in the axial channel 38 as the barrel 36 rotates the fin portion 34 between the retracted position and the extended position. In one aspect, the flared portion 62 can further comprise a second plurality of stop protrusions 64 for engaging the fin portion 34 and preventing over-rotation of the fin portion 34 past the deployed position.

(19) As depicted in FIG. 2, in one aspect, the cylindrical mount assembly 32 can further comprise a protector plate 66 shielding the ends of the drive axles 56 from damage from the heat and pressure generated during firing. The protector plate 66 can define a plurality of ports 68 for receiving corresponding fasteners 70 to secure the protector plate 66 to a corresponding plurality of ports 72 defined by the locking ring 44.

(20) According to an embodiment of the present invention, in operation, a projectile 20 can be loaded into a gun barrel or a tube launcher such that the tip portion 26 of the projectile 20 is oriented toward the muzzle of the barrel or tube launcher. In a gun launch, a propellant charge can be placed behind the fin deployment system 24. In a tube launch, a motor can be placed within the cylindrical mount assembly 32 or behind the fin deployment system 24. In one aspect, the fin cover 40 can be positioned over the fins 30 to retain the fins 30 in the retracted position while the projectile 20 is in the barrel or tube launcher.

(21) During firing, the propellant gases generated by the ignited propellant charge or the thrust generated by the launch motor accelerate the projectile 20 through the gun barrel or tube launcher. In a gun launch, the rifling of the barrel engages the projectile body 22 to impart spin to the projectile 20. In a tube launch, the motor can be aimed to impart a spin to the projectile 20 as the projectile 20 travels through the tube launcher and through the air. Similarly, the tip portion 26 of the projectile body 22 can comprise air scoops shaped to cause axial rotation of the projectile 20 in flight.

(22) Upon exiting the muzzle of the tube or barrel, the vents 74 in the fin cover 40 rapidly equalize the pressure within the fin cover 40 with the surrounding air. Aerodynamic drag on the fin cover 40 slows and separates the fin cover 40 from the fin deployment system 24. The axial rotation of the projectile 20 causes the now freed fin portions 34 to rotate into the deployed positions in response to the centrifugal forces created by the rotation of the projectile 20. The fin portions 34 continue to rotate until the barrel 36 engages the stop protrusion 46 preventing further rotation of the fin portion 34. Similarly, a locking tab 52 is then deployed from the cylindrical mount assembly 32 to engage the barrel 36 and prevent backwards rotation of the fin portion 34.

(23) While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and described in detail. It is understood, however, that the intention is not to limit the invention to the particular embodiments described. 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.