PROJECTILE DIVERTER RELEASE AND METHOD OF DIVERTING A PROJECTILE
A diverter for changing the trajectory of a projectile includes a release mechanism that extends along a longitudinal axis between first and second ends. A mass is coupled to the first end, and the second end is coupled to the projectile. The release mechanism includes a groove and an explosive charge. The groove is disposed between the first and second ends and cinctures the longitudinal axis. The explosive charge is disposed along the longitudinal axis between the groove and the second end.
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The present invention relates to controlling the flight path of rockets, missiles, and other flying projectiles. In particular, the invention relates to a small fast diverter for use with a projectile for steering the projectile in flight by ejecting a mass in response to a signal from a trajectory control system.
BACKGROUNDMissiles and projectiles historically have been guided by canting exhaust nozzles, moving fins or firing thrusters. Depending on the size and speed of the missile or projectile, most of these operate relatively slowly, re-directing the trajectory of the platform in small increments.
As the size of the missile or projectile becomes smaller and faster, many conventional divert or attitude control systems become too large and slow to provide sufficient trajectory change. For projectiles or missiles traveling at very high velocity or supersonic speeds and spinning, small rocket motors have been used to create side thrust to the body. These thrusters have limited impulse and fire over several milliseconds which results in “smearing” the thrust vector if the missile or projectile body is rotating.
Known devices provide divert impulses to a rotating projectile or missile using small slugs of high density metal that are released from the spinning body. These small slugs are released by generating a high pressure force, shearing pins or other retention mechanisms. These known devices must be sufficiently robust to withstand high internal pressure which adds weight and volume. The use of a propellant or pyrotechnic for the pressure generating medium limits the reaction time to milliseconds.
A conventional missile or projectile includes a matrix or array of thrusters or slug diverters. As each thruster or diverter is fired, the original trajectory of the missile or projectile is altered. The reaction time of these thrusters or diverters is slow, there are fewer opportunities to make one or more trajectory changes.
Embodiments according to the present disclosure include various projectile diverters for improving slug ejection reaction time. Additionally, thrust may be improved, especially for very high velocity projectiles spinning at extreme spin rates, at least in part because the retention mechanisms of the projectile diverters contribute to the mass of the slugs that are ejected.
At least some embodiments according to the present disclosure may include a large number of projectile diverters in a small volume to provide a broad selection of projectile diversion control. Additionally, these projectile diverters are immune to high axial acceleration spin rates and adjacent pyrotechnic shocks.
At least some embodiments according to the present disclosure may include metal slugs or high density masses that are released at a precise rotational angle to provide radial impulse. The slugs or masses may be deployed individually, simultaneous or sequentially to affect the desired trajectory alteration of a projectile in flight. Because higher projectile spin rates increase the centrifugal force acting on the slugs or masses; accordingly, very strong mechanisms are required to attach the slugs or masses to the projectile prior to release.
At least some embodiments according to the present disclosure may include an explosive bolt release mechanism that provides retention while in extreme G-force environments, and also releases the slugs or masses within microseconds of a FIRE command. The explosive bolt may be configured to occupy little volume and be protected from adjacent slugs and have a pre-determined separation plane.
In at least some embodiments of the present disclosure, slug or mass release can be consistently predicted because the separation plane of the explosive bolt includes a groove that can be adjusted within demonstrated margins without changing the internal components of the release mechanisms. The slug or mass has an inside diameter that provides a clearance between it and the explosive bolt. This clearance allows the explosive bolt to expand without transmitting pyro shock to adjacent slugs or projectile structure, thereby also providing 360 degree protection from adjacent slugs and explosive bolts.
According to at least some embodiments of the present disclosure, when a projectile or missile is launched, the acceleration loads are normal to the longitudinal axis of the explosive bolt release mechanism and do not tend to move or displace the release mechanism internals. When the projectile begins to spin, the centrifugal force pulls on the slugs or masses, thereby tensioning the bolt. When release is initiated, the explosive charge severs the bolt by shock wave interaction rather than by pressure.
B. Embodiments of Projectile Diverter Release MechanismsThe slug mass 200 may be coupled to the release mechanism 100 by a threaded connection or another suitable mechanical connection. According to one embodiment, the release mechanism 100 includes a first set of screw threads 102 that cooperatively engage a second set of screw threads 202 on the slug mass 200.
The bolt body 110 extends along a longitudinal axis L-L between a first end 112a and a second end 112b. The first set of screw threads 102 is disposed on an outer surface 114 of the bolt body 110 proximate the first end 112a and a third set of screw threads 104 is disposed on the outer surface 114 proximate the second end 112b. The third set of screw threads 104 provides a coupling between the slug 30 and a fourth set of screw threads (not shown) on the projectile 10.
The outer surface 114 of the bolt body 110 may include a shoulder 116 and a groove 118. The shoulder 116 may provide a limit stop for the slug mass 200 with respect to the bolt body 110. In particular, the shoulder 116 may contiguously engage a corresponding boss 204 provided on an inner surface 204a of the slug mass 200 (
The groove 118 provides a pre-determined separation plane X-X between the first end 112a and the second end 112b of the bolt body 110. The geometry and location of the groove 118 are selected to minimize the amount of the explosive charge 130 that is needed to cause separation. In particular, the depth and location along the longitudinal axis L-L of the groove 118 may be selected based on the tested structural properties of an individual batch of bolt bodies 110. Accordingly, the same explosive charge 130 may be used consistently and the groove 118 varied to achieve the desired separation in the actuated configuration of the slug 30 (
Referring to
The outer surface 114 of the bolt body 110 may also include a fitting recess 128 at the first end 112a of the bolt body 110. The fitting recess 128 may receive a torque applying tool (not shown) that may be used, e.g., for turning the slug 30 so that the third set of screw threads 104 couples to the fourth set of screw threads (not shown) on the projectile 10. The recess fitting 128 may include, for example, a slot to receive a flat blade screwdriver, a hexagonal hole to receive an Allen wrench, or another configuration suitable to receiving a correspondingly shaped tool.
The bolt body 110 may be fabricated from high-strength stainless steel. For example, the bolt body 110 may include Inconel 718 or another material having an ultimate tensile strength of approximately 180,000 to 220,000 pounds-per square-inch (psi), a minimum yield strength of approximately 160,000 psi, and a hardness of approximately 40-46 (Rockwell C).
Referring additionally to
The header body 154 can include stainless steel for welding compatibility with the bolt body 110. This provides a solid attachment for the squib assembly 150 to the bolt body 110, as well as provides a hermetic seal to protect the contents in the passageway 122a and to provide a long shelf and service life.
The squib assembly 150 receives the FIRE signal from the trajectory control system 12. Upon receiving the FIRE signal, the heating element 170, which may include a Thin Film Bridge (TFB), heats rapidly setting off the ignition charge 176. According to one embodiment, the ignition charge 176 includes potassium dinitrobenzofuroxan or “KDNBF” (potassium 4,6 dinitro-7 hydroxy-7 hydro-benzofuroxan). The ignition charge 176 may also be pressed in the body at high pressure to mitigate movement in high G-force environments. The squib assembly 150 is fabricated separately from the bolt body 110 and can therefore be acceptance tested separately from the bolt body 110. The output of the squib assembly 150 reacts at detonation velocity, e.g., approximately 6,000 to 8,000 meters-per-second, so that the total function time is very short, e.g., 50 to 100 microseconds.
As shown in
If the intended trajectory of the projectile 10 is in a direction D1, but the projectile 10 is traveling is in a direction D2, one or more slugs 30 from the array 20 can be released to divert the projectile 10 toward direction D1. The trajectory control system 12 issues a FIRE command and the slug(s) 30 transition within microseconds, e.g., in less than 100 microseconds or approximately 50 microseconds, from the unactuated configuration (
From the foregoing, it will be appreciated that specific embodiments of the disclosure have been described herein for purposes of illustration, but that various modifications can be made without deviating from the spirit and scope of the disclosure. For example, it may be desirable to have from one to 64 or more slugs on a projectile. Additionally, it may be desirable to orient the longitudinal axes of the slugs obliquely and/or tangentially with respect to the longitudinal axis of a projectile. Moreover, specific elements of any of the foregoing embodiments can be combined or substituted for elements in other embodiments. Furthermore, while advantages associated with certain embodiments of the disclosure have been described in the context of these embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, embodiments of the disclosure are not limited except as by the appended claims.
Claims
1. A diverter for a projectile, comprising:
- a mass; and
- a release mechanism extending along a longitudinal axis between a first end coupled to the mass and a second end configured to couple to the projectile, the release mechanism includes— a groove disposed between the first and second ends and cincturing the longitudinal axis; and an explosive charge disposed along the longitudinal axis between the groove and the second end.
2. The diverter according to claim 1 wherein the release mechanism comprises an unactuated arrangement and an actuated arrangement.
3. The diverter according to claim 2, wherein a time period to transition from the unactuated arrangement and the actuated arrangement is less than 100 microseconds.
4. The diverter according to claim 3, wherein the time period is approximately 50 microseconds.
5. The diverter according to claim 2, wherein, the unactuated arrangement includes the release mechanism retaining the mass on the projectile, and the actuated arrangement includes the release mechanism releasing the mass from the projectile.
6. The diverter according to claim 2, wherein the mass is coupled to the first end in the actuated arrangement and decoupled from the second end in the actuated arrangement.
7. The diverter according to claim 1, wherein the mass and the first end are threadably coupled.
8. The diverter according to claim 1, wherein the mass extends along the longitudinal axis between a fixed end coupled to the first end and a free end disposed along the longitudinal axis between the groove and the second end.
9. The diverter according to claim 8, wherein the free end cinctures the release mechanism.
10. The diverter according to claim 9, further comprising an annular gap between the free end and the release mechanism.
11. The diverter according to claim 1, wherein the release mechanism comprises an explosive bolt.
12. The diverter mechanism according to claim 11, wherein the explosive bolt comprises a first set of screw threads at the first end and a second set of screw threads at the second end.
13. The diverter according to claim 1, wherein the release mechanism further comprises an electrically operated heating element.
14. The diverter according to claim 13, wherein the electrically operated heating element comprises a thin film bridge.
15. The diverter according to claim 1, wherein the explosive charge comprises an ignition charge, a primary explosive material, and a secondary explosive material.
16. The diverter according to claim 15, wherein the release mechanism further comprises an electrically operated heating element configured to ignite the ignition charge, wherein the ignition charge is configured to detonate the primary explosive material, and wherein the primary explosive material is configured to detonate the secondary explosive material.
17. The diverter according to claim 1, wherein the release mechanism comprises a bolt body cincturing a passageway extending along the longitudinal axis from the second end to a closed end, wherein the closed end is disposed between the groove and the second end, and wherein the explosive charge comprises a secondary explosive material pressed against the closed end.
18. The diverter according to claim 17, wherein the secondary explosive material is configured to separate the first and second ends by shock wave interaction at the groove.
19. The diverter according to claim 17, wherein the release mechanism comprises a squib assembly occluding the passageway proximate the second end.
20. The diverter according to claim 19, wherein the squib assembly is hermetically coupled to the bolt body.
21. The diverter according to claim 19, wherein the squib assembly comprises a head body, a plurality of electrical leads extending through an aperture in the head body, and an insulator hermetically sealing the electrical leads and the head body.
22. The diverter according to claim 21, wherein the squib assembly comprises an electrostatic spark discharge gap between the head body and the plurality of electrical leads.
23. A projectile comprising:
- a body extending along a first axis between a nose and a tail; and
- an array of diverters configured to divert a trajectory of the body, wherein individual diverters include an explosive bolt extending along a second axis between a first end having a mass and a second end coupled to the projectile, and wherein the explosive bolt couples the first end to the projectile in an unactuated arrangement and the explosive bolt decouples the first end from the projectile in an actuated arrangement.
24. The projectile according to claim 23, wherein the second axes are non-parallel to the first axis.
25. The projectile according to claim 23, wherein the second axes are approximately perpendicular to the first axis.
26. The projectile according to claim 23, wherein the second axes are non-parallel to the first axis.
27. The projectile according to claim 23, wherein the array of diverters comprise a plurality of diverters having individual second axes disposed at different angular positions about the first axis.
28. A method of diverting a projectile from a first trajectory to a second trajectory, comprising:
- separating a bolt body coupling a mass to the projectile, wherein an unseparated arrangement of the bolt body retains the mass on the projectile and a separated arrangement of the bolt body releases the mass off the projectile, and wherein separating the bolt body occurs in less than 100 microseconds.
29. The method according to claim 28, wherein separating the bolt body occurs in approximately 50 microseconds.
30. The method according to claim 28, wherein separating the bolt body comprises detonating an explosive charge between ends of the bolt body.
31. The method according to claim 28, wherein separating the bolt body comprises generating shock wave interaction at a groove cincturing the bolt body.
Type: Application
Filed: Feb 25, 2010
Publication Date: Aug 25, 2011
Applicant: Pacific Scientific Energetic Materials Company (Valencia, CA)
Inventors: Robert S. Ritchie (Newhall, CA), Steven Stadler (Castaic, CA)
Application Number: 12/713,161
International Classification: F42B 10/32 (20060101);