WO2009005540A1

WO2009005540A1 - Systems and methods for a projectile having a stabilizer for spin stabilization

Info

Publication number: WO2009005540A1
Application number: PCT/US2007/087814
Authority: WO
Inventors: William David Gavin; Dubravko Zekonovic
Original assignee: Taser International, Inc.
Priority date: 2007-06-29
Filing date: 2007-12-17
Publication date: 2009-01-08

Abstract

A round, according to various aspects of the present invention, launches an electrified projectile for spin stabilized flight. The projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions. The projectile includes a body and a stabilizer. The stabilizer has a first torsion stored along a first axis and a second torsion stored along a second axis. Torsions are released to deploy the stabilizer and to bias the stabilizer during flight.

Description

SYSTEMS AND METHODS FOR A PROJECTILE HAVING A STABILIZER

FOR SPIN STABILIZATION

CROSS-REFERENCE TO RELATED APPLICATIONS US Patent Applications by Dave Gavin, et al., entitled "Systems and Methods for Unfastening a

Film of an Electrified Projectile", "Systems and Methods for Placing Electrodes", "Systems and Methods for Deploying an Electrode Using Torsion", and "Systems and Methods for a Rear Anchored Projectile", incorporated herein by reference, and the present application are all commonly owned and are all filed June 29, 2007.

FIELD OF THE INVENTION

Embodiments of the present invention relate to systems and methods for in-flight spin stabilization of a projectile.

BACKGROUND OF THE INVENTION

Accuracy of a projectile launched from a barrel is improved by imparting spin to the projectile for spin stabilization during flight. Smooth bore barrels cannot impart spin to a projectile while the projectile transits the barrel. For a projectile designed to be launched from a standard diameter smooth bore barrel, size and weight restrictions prevent the use of conventional technologies for spin stabilization. Consequently, greater accuracies cannot be obtained and the applications for projectiles launched from smooth bore barrels are limited.

SUMMARY OF THE INVENTION

A round, according to various aspects of the present invention, includes an electrified projectile. The round includes a body and a stabilizer. The stabilizer has a first torsion stored along a first axis and a second torsion stored along a second axis. Torsions are released to deploy the stabilizer for spin stabilized flight of the projectile. The projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions.

Another round, according to various aspects of the present invention, includes an electrified projectile. The round includes a body and a stabilizer. The body has a channel and an axis of the body.

The stabilizer has a loop and a rib. The loop is positioned in the channel. The rib is stowed parallel to the axis of the body prior to deployment of the stabilizer. The stabilizer is deployed for spin stabilized flight of the projectile. The projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions. A method, according to various aspects of the present invention, accomplishes assembling a round that includes an electrified projectile. The projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions. The method includes, in any practical order: (a) storing a first torsion in a stabilizer of the projectile along a first axis; (b) storing a second torsion in the stabilizer along a second axis; and (c) loading the round with the projectile so that the first torsion and the second torsion deploy the stabilizer after the projectile is launched from the round.

Another method, according to various aspects of the present invention, accomplishes assembling a round that includes an electrified projectile. The projectile has a body and a stabilizer. The projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions. The method includes, in any practical order: (a) positioning a spring of the stabilizer in a channel around an axis of the body; (b) stowing a rib of the stabilizer parallel to an axis of the body; (c) stowing a surface of the stabilizer along the body; and (d) loading the round with the projectile so that the spring deploys the stabilizer after the projectile is launched from the round.

BRIEF DESCRIPTION OF THE DRAWING Embodiments of the present invention will now be further described with reference to the drawing, wherein like designations denote like elements, and:

FIG. 1 is a perspective plan view of an electrified projectile, according to various aspects of the present invention, prior to loading the projectile into a shell, the shell having a propellant to launch the projectile; FIG. 2 is a perspective plan view of the projectile of FIG. 1 in flight;

FIG. 3 is a perspective plan view of the projectile of FIG. 1 during recoil after impact; FIG. 4 is a cross-section of a round including the projectile of FIG. 1 ; FIG. 5 is an enlarged cross-section of region 405 of FIG. 4;

FIG. 6 is a perspective plan view of a portion of the projectile of FIG. 1 with stabilizers and electrodes deployed;

FIG. 7 is a perspective plan view of the projectile of FIG. 6 with torsion stored along an axis tangent to each loop;

FIG. 8 is a perspective plan view of the projectile of FIG. 6 with torsion stored along an axis of each rib; FIG. 9 is rear view of the projectile of FIG. 2;

FIG. 10 is a perspective plan view of stabilizer 112 of FIG. 1 ; and FIG. 11 is a functional block diagram of the round of FIG 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A projectile fired from a smooth bore barrel has a trajectory that is guided by the barrel until the projectile exits the barrel. After leaving the barrel, momentum may carry the projectile generally along the trajectory of barrel orientation. However, the projectile may leave the desired trajectory. Leaving the desired trajectory results in inaccurate delivery. Conventional projectiles have a front portion. In many applications, it is important for the front portion to hit the target before any other portion of the projectile hits the target. This sequence is accomplished by maintaining the orientation of the projectile throughout flight. Failure to maintain the orientation of the projectile during flight is herein referred to as instability. It is well known to spin a projectile during flight so that gyroscopic forces maintain stability. Spin may be imparted by a surface that is subject to aerodynamic forces. According to various aspects of the present invention, after a projectile is launched from a barrel, one or more surfaces that impart spin may be deployed (e.g., moved to a position more affected by aerodynamic forces). A surface that deploys after launch may be prepared for deployment such that, in a stowed position, the deployment mechanism and the surface occupy little space in the projectile. A round that includes an electrified projectile, according to various aspects of the present invention, maintains the projectile in a stowed condition until after launch. The round may include a propulsion system (e.g., pyrotechnic shell) and/or cooperate with a propulsion system (e.g., compressed air). Launching propels the projectile away from the round (e.g., out of a shell) and through a smooth bore barrel for impact with a human or animal target. It is desirable that the impact of the projectile with the target not cause serious injury to the target due to blunt force. Consequently, light weight electrified projectiles with relatively low muzzle velocity are desirable.

An electrified projectile includes any apparatus that establishes a circuit through the target for delivery of a stimulus signal for immobilizing the target. An electrified projectile may include an energy source (e.g., battery, charged capacitor), a circuit (e.g., signal generator and controls), and one or more electrodes. The signal generator provides an electrical stimulus signal (e.g., current) in a circuit through the electrodes and through the target sufficient to cause contraction of skeletal muscles to immobilize the target. One or more electrodes for establishing a suitable circuit for the current may be fixed to portions of the projectile or launched from the projectile (e.g., wire-tethered to a portion of the projectile). Portions of the projectile may separate from each other in flight or after impact with a target to accomplish suitable spacing between electrodes. Electrode spacing of at least 6 inches is believed to be effective for immobilization. Delivery of the electrified projectile to the target with the desired orientation improves the likelihood of establishing a circuit with suitable electrode spacing. For an electrified projectile application, accuracy refers to effective placement of electrodes into the target at a suitable spacing.

An electrified projectile according to various aspects of the present invention performs the functions and overcomes the problems discussed above. For example, electrified projectile 100 of FIGs. 1 - 11 exhibits improved accuracy and stability. Electrified projectile 100 of FIG. 1, shown prior to loading the projectile into a shell, includes body 102 and nose 106. Body 102 includes a battery (not shown), a circuit having a signal generator (not shown), an activation strap 103, film 104, and three stabilizers 112a, 112b and 112c (shown in FIG. 5). Film 104 includes six tabs to retain each stabilizer in a stowed position of which tabs 110a and 110b are shown retaining stabilizer 112b. Body 102 further includes three spurs, each spur includes a pair of spike electrodes. Stimulus current generally flows through a circuit that includes at least one frontal electrodes of the nose, tissue of the target, and at least one spike electrode of the body. A body defines the shape of the electrified projectile, orients electrodes, and houses the battery and circuitry of the electrified projectile. The shape of the body may improve accuracy and/or stability of the electrified projectile. The body may permit portions of the electrified projectile to be deployed at different times. For example, body 102 is substantially cylindrical about a central axis 180 for packaging the projectile in a shell and launching the projectile from a smooth bore. Body 102 and nose 106 are coupled (e.g., by rigid attachment until impacting the target) to orient the nose to the direction of delivery along body axis 180. Nose 106 is intended to impact the target before any other part of the projectile impacts the target. In flight, body 102 spins on body axis 180.

A nose retains electrodes, orients electrodes, controls the amount of separation between frontal electrodes while becoming embedded into the tissue of a target, and/or affects the amount of momentum delivered by the electrified projectile to the target at impact. A nose includes the forward portion of the electrified projectile relative to the direction of delivery. For example, nose 106 retains a plurality 108 of frontal electrodes including electrodes 108a, 108b, 108c, and 108d. Nose 106 orients frontal electrodes 108 along the direction of delivery. Nose 106 may include one or more rear-facing electrodes (e.g., rear- facing electrode 306 of FIG. 3). Target movement may establish contact with a rear-facing electrode as described in US Patents 7,042,696 and 7,057,872, and US Patent Application 10/750,374 filed Dec. 31, 2003 all incorporated herein by reference.

Coupling between nose 106 and frontal electrodes 108 may affect an amount of change in electrode spacing upon entry of electrodes 108 into target tissue (not shown). In one implementation, frontal electrodes 108 are flexibly mounted to nose 106 to diverge. The distance between the respective tips of the frontal electrodes may increase as the electrodes enter target tissue. An increase in the distance between frontal electrode tips may increase the ability of frontal electrodes 108 to remain embedded in target tissue. Each frontal electrode 108a, 108b, 108c, and 108d may include a barb to increase the likelihood of frontal electrodes 108 remaining embedded in target tissue.

The material forming nose 106 may affect an amount of momentum transferred from electrified projectile 100 to the target at impact. In one implementation, nose 106 is made of a relatively flexible material that flexes upon impact to distribute the force of impact over a larger area or to transfer momentum to body 102. Any conventional rubber or plastic may be used. Foam may be used.

An electrified projectile may have a limited function state and a full function state. The limited function state facilitates storing the projectile for an extended period. In a limited function state, the electronics of the projectile consume little or no power (e.g., the projectile is "off) . The full function state includes the function of producing a stimulus signal through target tissue (e.g., the projectile is "on"). An activation strap includes any structure that facilitates switching operation of the projectile from a limited function state to a full function state. An activation strap may separate a battery from a circuit that would otherwise be in physical contact (e.g., urged together and held in electrical contact by a resilient material). For example, strap activation 103 maintains an open circuit between a battery and a signal generator of projectile 100. During launch, activation strap 103 is pulled away from body 102 and is not part of the projectile in flight or on impact.

A film includes any thin sheet structure that holds a stabilizer. A stabilizer may have a stowed position against the projectile and a deployed position away from the projectile. Stabilizers may be maintained in a stowed position by a film. The film may have tabs that partially cover a stabilizer. Tabs may retain a stabilizer in a stowed position as the projectile is inserted into a case, as the projectile exits the case, and as the projectile transits the barrel during launch. For example, film 104 comprises a thin sheet of plastic having tabs (e.g., 110a and 110b) integral with the sheet to hold a stabilizer (e.g., 112b) in a stowed position of the stabilizer. Stabilizers 112a and 112c are held by additional tabs (not shown) of film 104. Tabs 110a and 110b assist to retain stored torsion in stabilizer 112b and protect stabilizer 112b during launch. In the stabilizer's stowed position, tabs 110a and 110b partially cover stabilizer 112b from a time before projectile 100 is inserted into a case of a round to a time after the projectile is launched from the round into a barrel and leaves the barrel. In a preferred implementation tabs 110a and 110b are not shaped to retain a stabilizer outside a shell unassisted by manufacturing tooling yet are sufficient for assisting in handling a projectile 100 (e.g., preparing for insertion of projectile 100 into a holding fixture or into a shell).

Film 104 includes an opening for each stabilizer that permits each stabilizer to remain attached to body 102, be positioned in its stowed position, and be deployed without interfering with the position of film 104 about body 102. For example, stabilizer 201 is assembled onto body 102 before film 104 is wrapped about body 102. Opening 212 permits film 104 to avoid interference with stabilizer 201 as film 104 is wrapped around body 102 and fastened to remain surrounding body 102.

A body and a nose may have, with respect to each other, an engaged relationship and a disengaged relationship. By maintaining the engaged relationship until impact with a target, the aerodynamics of a projectile may be controlled primarily by stabilizers. A disengaged relationship facilitates placement of electrodes into the target. The body may have electrodes and the nose have additional electrodes. After being disengaged, the electrodes of the body may impact the target a suitable distance from electrodes of the nose. For example, projectile 100 as shown in flight in FIG. 2 spins due to stabilizers 200 and maintains an engaged relationship between body 102 and nose 106 until impact with a target (not shown). After impact, body 102 and nose 106 attain a disengaged relationship as shown in FIG. 3 and spike electrodes 312 are deployed. Impact may release one or more fasteners (e.g., frangible plastic fasteners) that when released allow body 102 and nose 106 to move independently of each other. When impact lodges nose 106 in target tissue, body 102 dissipates the kinetic energy remaining after impact.

A stabilizer, according to various aspects of the present invention, includes any aerodynamic structure that improves accuracy and/or stability. A stabilizer may maintain travel of the electrified projection along a desired path. A stabilizer may maintain the orientation of an electrified projectile in flight. A stabilizer may improve stability by controlling the movement of the projectile. A stabilizer may impart or increase a rotational force to an electrified projectile. A stabilizer may translate an aerodynamic pressure into spin of the projectile. A stabilizer may impart or increase a drag force on the electrified projectile. A stabilizer may include streamers trailing from the projectile to increase a drag force. For example, stabilizers 112a, 112b, and 112c (renumbered 201, 202, and 203 in FIGs. 2, 3, and 6-10) when deployed impart spin to electrified projectile 100 about body axis 180 in a clockwise direction viewed from the rear.

Deployment of a stabilizer may be affected by releasing torsion. A stabilizer may consist essentially of two structures: a surface for translating an aerodynamic force into motion of the projectile, and a support that positions the surface for aerodynamic effect. Deployment positions the surface for aerodynamic effect. According to various aspects of the present invention, a stabilizer has a frame that acts as a support and is capable of storing and releasing torsion to affect deployment. For example, projectile 100 of FIG. 2 includes a plurality 200 of stabilizers. Each stabilizer 201 (202, 203) includes a frame 201a (202a, 203a) and a surface 201b (202b, 203b). Each frame includes a rib 201c (202c, 203c).

A film may have a stowed position and a deployed position. The stowed position may hold stabilizers in each stabilizer's stowed position as discussed above. The stowed position may also hold spike electrodes in a stowed position. The deployed position of the film may facilitate deployment of spike electrodes. Movement of the film from the stowed position to the deployed position may be facilitated by release of a fastener and release of a torsion of the film. The film may include a resilient material for storing torsion. The fastener may comprise features integral to the film. Perforations through the film and a thread may form a fastener. For example, film 104 is formed of one resilient sheet material that stores torsion when wrapped about body 102. Film 104 includes perforations (e.g., perforation 220) that permit a thread to sew portions of film 104 together so that film 104, despite the torsion of its resilient material, remains wrapped about body 102 as long as thread 216 is in place.

A thread includes any structure for closing a film through perforations in the film. A thread, according to various aspects of the present invention, releases the film in cooperation with disengagement of the body and nose. For example, thread 216 may be formed of spring wire for resistance to corrosion. Thread 216 is wrapped about frontal electrode 108d so that rearward recoil of body 102 after impact of nose 106 with a target urges film 104 to withdraw away from thread 216, releasing film 104 from its stowed position. Thread 216 may be uninsulated to provide an extension of electrode 108d. If another part of the target comes into contact with thread 216, a suitable circuit for conducting stimulus current through the target may be formed.

A film may cooperate with a nose to deploy spike electrodes. A film may provide time delayed deployment of portions of an electrified projectile. A film may delay the release of electrodes until the projectile impacts a target. Retaining electrodes beneath a film decreases drag that deployed electrodes may provide during flight. For example, body 102 includes three pairs of spike electrodes 312 that are not deployed until film 104 is removed by separation of body 102 from nose 106. Film 104 retains spike electrodes 312 in a stowed position. Before inserting electrified projectile 100 into case 410, film 104 encircles body 102 and spike electrodes 312. After projectile 100 exits the barrel, tabs of film 104 release stabilizers 200, but film 104 retains spike electrodes 312. Film 104 is retained in an encircling position around body 102 by a fastener. In a relaxed state, film 104 is substantially rectangular in shape having perforations 220 at opposing edges. Spike electrodes 312 are held in a stowed position and encircled with film 104. Thread 216 is inserted through perforations 220 to retain film 104 in the encircled position.

Upon impact, frontal electrodes 108 embed into target tissue and nose 106 strikes the target. Barbs on frontal electrodes 108 help retain frontal electrodes 108 in target tissue such that the nose 106 remains against the target. The recoil force from impact causes body 102 to unfasten and then separate from nose 106. During separation, nose 106 retains thread 216. As body 102 pulls away from nose 106, thread 216 is pulled from perforations 220. Once thread 216 is free from film 104, the torsion stored in film 104 and in spike electrodes 312 pushes film away from body 102 and spike electrodes 312 move to a deployed position. Film 104 falls away. When disengaged from a nose, a body and nose may remain electrically and mechanically coupled. Mechanical coupling may provide strain relief to preserve the electrical integrity of the electrical coupling. A filament between a nose and a body may protect conductors between a signal generator in the body and electrodes in the nose. The filament may also redirect movement of the body with respect to the nose. Assuming for example that the nose is embedded in a target by impact with the target, a recoil force from this impact generally forces the body to move away from the nose and consequently away from the target. The force applied on the filament when the filament reaches its greatest extent redirects the movement of the body toward the target. As a consequence of the filament, upon impact of electrodes in the nose with the target, the body of the electrified projectile moves initially away from the target then moves toward the target. Movement of the body toward the target embeds spike electrodes in the target a distance away from the electrodes in the nose.

For example, filament 314 is shorter than conductors 316 and formed of a non-elastic fiber (e.g., a poly-paraphenylene terephthalamide of the type marketed as Kevlar®). Conductors 316 electrically couple frontal electrodes 108 to a signal generator in body 102. Conductors 316 are wound about body 102 when body 102 is engaged with nose 106. When disengaged, conductors 316 unwind allowing separation between body 102 and nose 106 without loss or change in electrical coupling. Filament 314 mechanically couples nose 106 to body 102 to relieve strain in conductors 316 when body 102 pulls away from nose 106.

As body 102 moves away from nose 106 due to the recoil force of impact, filament 314 extends to its maximum length (e.g., from about 6 to about 24 inches). At its maximum extent, filament 314 may stop the movement of body 102 away from the target to protect conductors 316 from stretching or electrical decoupling. Filament 314 further redirects the movement of body 102 away from the target to movement toward the target such that spike electrodes 312 are embedded into the target at a distance away from frontal electrodes 108. In an accurate impact, a circuit path between embedded frontal electrodes 108 and embedded spike electrodes 312 is at least six inches long.

Separation of nose 106 from body 102 exposes one or more rear-facing electrodes (e.g., 306). Rear-facing electrode 306 may come into contact with the target through movement of the target as discussed above. For instance, in the event that nose 106 impacts the target's chest and rear-facing electrode 306 comes into contact with the hand of the target, the projectile may deliver a stimulus signal on a path at least the length of the target' s arm, a distance typically greater than the distance between frontal electrodes 108.

Conductors between the body and the nose conduct a stimulus signal between a signal generator and the frontal electrodes. Any portion of any conductor between the body and the nose may comprise uninsulated, exposed, conductor to serve the same function as a rear-facing electrode as discussed above. A round includes any apparatus for launching an electrified projectile. A round may omit a propellant when for example the round is for use with a launching apparatus that includes a supply of propellant (e.g., a launcher having a compressed air supply). Any conventional method of propelling a projectile may be used. An electrified projectile may include a propulsion system and/or propellant. A launching apparatus and/or a round may facilitate the simultaneous launching of any number of electrified projectiles. A round may include a case and a base having a form factor and made of materials suitable for use in a conventional weapon for breach loading or muzzle loading (e.g., cannon, mortar, 40 mm grenade launcher, flare gun, musket, 12-guage shotgun, 20-guage shotgun, pistol). The weapon may initiate launch of the projectile by any conventional apparatus (e.g., percussion firing pin, switched electrical current). For example, round 400 of FIG. 4 includes case 410, base 402, and projectile 100 for launching the projectile from a propellant in the base.

A case attaches to a base to provide a chamber for directing the expanding gases of a propulsion system to launch a projectile. For example, round 400 for a shotgun includes a cylindrical case 410 (e.g., 12 guage) that is closed at the front to keep moisture and foreign materials away from projectile 100. A base includes any apparatus for locating a case within a barrel for launching a projectile. For example, base 402 may include a propellant to launch projectile 100, a percussion fired propulsion system (e.g., gun powder), and a retaining plate. Propellant is sufficient for a muzzle velocity of less than 400 feet per second for a projectile of about 14 grams (about 12.5 grams for the body and conductors and about 1.5 grams for the nose). Muzzle velocity affects momentum delivered by the electrified projectile to the target at impact. Relatively low muzzle velocity decreases the amount of blunt impact force. In one implementation, muzzle velocity is about 310 feet per second. Muzzle velocity less than 400 feet per second is preferred.

By locating a portion of activation strap 103 behind retaining plate 403, activation strap 103 is retained in base 402 during and after launch. In the absence of activation strap 103, circuit 404 and battery 406 are pressed together in electrical contact, turning "on" the signal generator of circuit 404. A film may cooperate with a case. Tabs of a film may resiliently expand to press against the interior surface of a case. For example, in FIG. 5, pressure from case 410 on tab 510 of film 104 holds stabilizer 112c in the stowed position. When projectile 100 exits case 410, pressure from the barrel and tab 510 retains stabilizer 112c in the stowed position. Upon exit from the barrel, stabilizer 112c moves from its stowed position to its deployed position. Force from the movement to the deployed position overcomes the retention power of tab 510 such that stabilizer 112c pulls free from tab 510 to a final deployed position illustrated in FIGs. 2, 3, 6, and 9.

A stabilizer may include a structure that moves the stabilizer from a stowed position to a deployed position. In a deployed position, a stabilizer may operate to increase stability. A stabilizer may deploy by the release of torsion. Torsion may be stored and released along multiple axes. Deployment may release all or part of a stored torsion. Torsion used for deployment may be stored in the stabilizer during preparation for packaging the projectile into a round and/or during preparation of the stabilizer for deployment of the stabilizer. The structure or structures that store torsion may include resilient material formed as a spring. For example, stabilizers 200 each include a loop portion (e.g., a torsion spring) and an elbow that together support a rib as discussed above. The loop portion of each stabilizer 200 (e.g., 112c of FIG. 5) is pressed into a channel 514 of body 102. Channel 514 is circular about axis 180 and is of even depth throughout. Channel 514 retains all stabilizers 200 of projectile 100. The loop portions 511 and 512 of stabilizers 200 overlap within channel 514. Channel 514 may include an opening 601 that holds an elbow of each stabilizer to avoid slippage of stabilizers 200 relative to channel 514.

Body subassembly 600 of FIGs. 6, 7, and 8 may include spike electrodes 312 and stabilizers 200 shown in their deployed positions in FIG. 6 and shown just prior to attaching film 104. Spike electrodes are shown turned in their stowed positions and film 104 (omitted for clarity) retains them. Each of the spike electrodes 312 and the stabilizers 200 when deployed have released substantially all stored torsion.

Preparing a stabilizer of a projectile for insertion of the projectile into a case, according to various aspects of the present invention, includes storing torsion in a structure of the stabilizer. Each stabilizer 201, 202, and 203 is moved into its stowed position and partially covered by tabs of film 104. Moving a stabilizer into its stowed position stores torsion in two axes of rotation. This movement is described for each axis with reference to stabilizer 203 as follows. This movement may be accomplished with torsion being stored in both axes simultaneously, partially overlapping in time, or sequentially in any order.

Stabilizer 203 is rotated around axis 602 (a tangent of a centerline of loop 1002) and through an angle of about 90 degrees from the plane of loop 1002 until rib 203c is substantially parallel to body axis 180 (e.g., rib 203c is adjacent to or against body 102 as in FIGs. 1, 7 and 8). The rotation around axis 602 stores torsion in loop 1002 (e.g., torsion about a centerline of the loop) and/or elbow 1004 such that loop 1002 applies pressure to channel 514. Upon deployment, the stored torsion urges rib 203c away from body 102.

Stabilizer 203 is rotated around axis 604 within rib 203c such that surface 203d lies adjacent to or against body 102 as shown in FIG. 8. The rotation around axis 604 of rib 203c stores torsion in rib 203c and/or elbow 1004. Upon deployment, the stored torsion urges surface 203d away from body 102 to provide an angle 1102 to the plane of loop 1002. In the stowed position stabilizer 203 may store torsion around an axis within rib 203c and around a centerline of loop 1002.

Axes 602 and 604 each extend through elbow 1004. Each axis 602 and 604 lies within elbow 1004. An intersection of axes 602 and 604 may lie outside elbow 1004. A stabilizer may store torsions in two axes substantially in an elbow made of resilient material. In another implementation, a stabilizer having a living hinge in place of elbow 1004 discussed above, stores torsion for deployment substantially within the living hinge.

Stabilizer 203 of FIGs. 10 and 11 (exemplary of stabilizer 201 and 202) includes a frame formed from a continuous strand of wire. The frame includes a loop portion, an elbow, a rib portion, and a fin portion. Loop portion 1002 comprises about 240 degrees of a circle in a plane. Body axis 180 is perpendicular to this plane. Loop 1002 terminates at an elbow 1004 that makes a turn of about 90 degrees to form rib portion 203c. The strand may continue in any conventional manner to support plastic film for a fin portion. For example, a fin portion may be flat in a plane at an angle 1102 from the plane of loop 1002. Angle 1102 may be from about 80 degrees to about 20 degrees, preferably from about 70 degrees to about 50 degrees, most preferably 62 degrees plus or minus 5 degrees.

The frame of stabilizer 203 stores torsion, deploys the stabilizer, supports surface 203d, defines the shape of the surface 203d, and biases the stabilizer in the deployed position (e.g., effects a stiffness as surface 203d resists a resultant aerodynamic force not applied to spin). In other words, the frame portions of stabilizer 203 that store torsion for deploying stabilizer 203 also bias stabilizer 203 when deployed and during flight. A fin portion may be formed of plastic film (e.g., polyimide of the type marketed as Kapton®) and a pressure sensitive adhesive to form flat surfaces 203b and 203d. As the electrified projectile moves through the air, the atmosphere presses on surface 203d. Pressure on surface 203d is transferred into rib 203c and elbow 1004. Elbow 1004 enters body channel 514 through opening 212. Loop portion 1002 is positioned in channel 514. Force on surface 203d causes projectile 100 to spin and may also twist stabilizer 203 through rib 203c, elbow 1004, and loop 1002. Twisting may be resisted by the material of which the wire strand is made and/or by contact of loop 1002 with channel 514. The strand of wire for stabilizer 203 may have a diameter of about 0.015 inch and be formed of stainless steel (e.g., type 301) full hard spring temper with stress relieved after forming the shape described herein. Surface 203d may have any shape suitable for converting aerodynamic force into a force suitable for spinning projectile 100 with little or no wobble about body axis 180. Surface 203d (and 203b) may be substantially trapezoidal as shown substantially to scale in FIG.s 9-11 or substantially elliptical.

Fin stiffness influences the efficiency of translating aerodynamic force into force suitable for spinning projectile 100. A stiffer fin portion may cause more spin than a less stiff (e.g., more flexible) portion. Fin stiffness affects flight. A fin with greater stiffness reduces movement of the fin during flight. A fin with less stiffness permits the fin to rotate around the axis of rib 203c during flight (e.g., flutter). Fin flutter may increase stability.

In one implementation, frame 1004 is not rigidly connected to rib 1006 such that frame 1004 and rib 1006 do not form a closed geometric shape. The resulting frame stiffness permits fin 1008 to flutter back and forth during flight. Flutter may improve stability by permitting fins to dynamically adjust their angle of orientation to axis of body 180. Dynamic adjustment may improve stability by compensating for differences of fin orientation with respect to axis of body 180. Fin orientation may vary due to manufacturing tolerances.

The angle 1102 affects distance of forward travel for each revolution or rate of spin at a particular velocity. The surface may have a constant angle (as shown in FIGs. 1-11) or an angle that varies along the length of the rib. When angle 1102 is constant and about 62 degrees, the projectile travels about 21 inches forward for each revolution. A spin of less than 9000 revolutions per minute at a muzzle velocity less than 400 feet per second is preferred. Spinning creates centrifugal force on the components of projectile 100 that may be difficult to manage at higher rates of revolutions per minute.

A stabilizer may couple to a body in any manner suitable to impart spin. In one implementation, loop 1002 of stabilizer 203 couples to channel 514 of body 102. Aerodynamic force on stabilizer 203 may result in a force tangent to channel 514 thereby causing the electrified projectile to spin. Loop 1002 fits snugly in channel 514 to avoid or reduce slipping in response to the tangent force. As a fin portion in response to aerodynamic force biases the loop portion with torsion (instead of increasing spin), as discussed above, the friction of loop 1002 in channel 514 increases, further reducing slipping. In a preferred implementation, opening 212 includes a notch in body 102 so that elbow 1004 cannot slip in channel 514.

In another implementation of stabilizers 200, each loop portion (e.g., analogous to portion 1002) has a length of substantially a full circle (about 360 degrees as opposed to 240 degrees as shown). A loop portion may be formed of a closed circle. When the length of loop 1002 is about two-thirds of the circumference of a circle, overlap in channel 514 is at most two loops at any position along the channel.

A stabilizer may be formed of any material suitable for storing torsion force. For example, rib 1006, elbow 1014, and loop 1012 may be formed of highly resilient material. For example, elbow 1004, and loop 1002 may be formed of wire with a diameter of about 0.015 inch of stainless steel (e.g., type 301) full hard spring temper with stress relieved after forming the shape described herein.

A stabilizer may conduct some or all of the stimulus current through the target. A conductive stabilizer may form a circuit between a signal generator and the target for delivery of a stimulus signal (e.g., current) through the target. A conductive stabilizer may have barbs to better connect to the target. A round may include an apparatus that propels an electrified projectile. A round may package a propulsion system with an electrified projectile. A round may be activated by a launch device to propel the projectile. A round may position a propulsion system and a projectile such that operation of the propulsion system launches the projectile toward a target. An electrified projectile delivers a stimulus signal through the target without a connecting or conducting tether between the projectile and a weapon or between the projectile and a base of a round.

For example, round 1200 of FIG. 12 includes propulsion system 1202 and projectile 1204. In operation, round 1200 is placed in a weapon. The weapon provides a launch signal or action received by propulsion system 1202. Responsive to the launch signal or action, propulsion system 1202 launches projectile 1204 out of the weapon and toward a target. An electrified projectile includes any apparatus that travels toward a target, places electrodes on a target, and delivers a stimulus signal from a circuit of the projectile through the electrodes and through the target. An electrified projectile may deliver a stimulus signal by transporting to the target a source of energy and a signal generator. For example, projectile 1204 includes battery 1206, switch 1208, signal generator 1210, electrodes and stabilizers 1212, and deployment apparatus 1214. Deployment apparatus 1214 deploys an electrodes and stabilizers. Examples of deployment of electrodes and stabilizers are discussed above. Battery 1206 provides energy to signal generator 1210 to provide a stimulus signal through the deployed electrodes and through the target. Switch 1208 couples battery 1206 to signal generator 1210. Switch 1208 may be closed to provide energy to signal generator 1210 at any time. For example, switch 1208 may be closed for a short period during assembly of round 1200 for testing. Switch 1208 may be closed upon insertion of round 1200 into a weapon. To conserve battery power, switch 1208 may be closed upon impact of projectile 1204 with a target. Preferably, switch 1208 is closed upon launch of projectile 1204 so that signal generator 1210 prepares a stimulus signal during flight. Conserving battery power may increase a duration of providing a stimulus signal through the target.

The foregoing description discusses preferred embodiments of the present invention which may be changed or modified without departing from the scope of the present invention as defined in the claims. While for the sake of clarity of description, several specific embodiments of the invention have been described, the scope of the invention is intended to be measured by the claims as set forth below.

Claims

CLAIMSWhat is claimed is:

1. An round that launches an electrified projectile, the round comprising: a body; and a stabilizer having a first torsion stored along a first axis and a second torsion stored along a second axis, wherein the first torsion and the second torsion are released to deploy the stabilizer for spin stabilized flight of the projectile; and the projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions.

2. The round of claim 1 wherein movement of the stabilizer from a stowed position to a deployed position releases the first torsion and second torsion.

3. The round of claim 1 wherein: the stabilizer comprises a surface for imparting spin to the projectile; and release of the first torsion moves the surface away from the body.

4. The round of claim 3 wherein release of the second torsion moves the surface into a position for imparting spin to the projectile.

5. The round of claim 3 wherein: the stabilizer comprises a rib; and release of the second torsion moves the rib away from the body.

6. The round of claim 3 further comprising a tab that retains the surface adjacent to the body prior to deployment of the stabilizer.

7. The round of claim 1 wherein the stabilizer comprises a loop in a plane that includes the second axis.

8. The round of claim 1 wherein the stabilizer comprises a rib that includes the first axis.

9. The round of claim 1 wherein the stabilizer delivers the current through the target.

10. The round of claim 1 wherein the stabilizer comprises a frame formed from a wire, the frame for storing the first torsion and the second torsion.

11. The round of claim 10 wherein: the frame comprises an elbow; and the first axis and the second axis are within the elbow.

12. The round of claim 1 wherein the stabilizer comprises an elbow, the first axis and the second axis being within the elbow.

13. A round that launches an electrified projectile, the round comprising: a body having a channel and an axis of the body; and a stabilizer that is deployed for spin stabilized flight of the projectile, the stabilizer having a loop and a rib, wherein the loop is positioned in the channel; the rib is stowed parallel to the axis of the body prior to deployment of the stabilizer; and the projectile provides a current through a target to incapacitate the target by causing skeletal muscle contractions.

14. The round of claim 13 wherein the rib rotates on an axis of the rib to deploy the stabilizer.

15. The round of claim 13 wherein the rib rotates on an axis tangent to a centerline of the loop to deploy the stabilizer.

16. The round of claim 13 wherein the stabilizer further comprises a trapezoidal fin supported by the rib.

17. A method for assembling a round that launches an electrified projectile, the projectile for providing a current through a target to incapacitate the target by causing skeletal muscle contractions, the method comprising: storing a first torsion in a stabilizer along a first axis; storing a second torsion in the stabilizer along a second axis; and loading the round with the projectile so that the first torsion and the second torsion deploy the stabilizer after the projectile is launched from the round.

18. The method of claim 17 further comprising securing the stabilizer in a stowed position of the stabilizer.

19. The method of claim 17 wherein the first torsion and the second torsion bias the stabilizer toward a deployed position.

20. The method of claim 17 wherein storing the first torsion comprises storing the first torsion in a rib of the stabilizer.

21. The method of claim 17 wherein storing the second torsion comprises storing the second torsion in a loop of the stabilizer.

22. The method of claim 17 further comprising combining a propellant with the round.

23. A method for preparing a round for deploying an electrified projectile for spin stabilized flight, the projectile for providing a current through a target to incapacitate the target by causing skeletal muscle contractions, the method comprising: positioning a spring of a stabilizer in a channel around an axis of a body of the projectile; stowing a rib of the stabilizer parallel to an axis of the body; stowing a surface of the stabilizer along the body; and loading the round with the projectile so that the spring deploys the stabilizer after the projectile is launched from the round.

24. The method of claim 23 wherein stowing the rib comprises rotating a rib of the stabilizer toward the body.

25. The method of claim 23 wherein stowing the surface comprises rotating the rib along an axis of the rib.

26. The method of claim 23 wherein stowing the rib stores a torsion in an elbow of the stabilizer.

27. The method of claim 23 wherein stowing the surface stores a torsion in an elbow of the stabilizer.

28. The method of claim 23 further comprising combining a propellant with the round.