Various surfaces are used to facilitate control of a craft's direction while in flight. The ability to control flight characteristics produces a stable flight path and permits controlled guidance of the craft. Flight controls typically include ailerons, an elevator, and a rudder. Flight controls in projectiles however, may be as simple as a set of tail fins to maintain stable flight along a desired path.
Many projectiles are fired or launched through a tube or barrel, necessitating the need for control surfaces that do not impede the projectile's path during launch. To accommodate this requirement, projectiles often utilize deployable control surfaces that extend outwards from the projectile after launch making it necessary to control when and how these control surfaces deploy. Various methods have been used, including explosively actuated or spring loaded control surfaces.
Methods and apparatus for an air brake system for a projectile according to various aspects of the present invention comprises a pivot and a protrusion mounted on the pivot. The protrusion is adapted to selectively translate outward from the projectile around a translation axis that is parallel to the longitudinal axis of the projectile. The methods and apparatus may further operate in conjunction with an actuation system engaging the protrusion, wherein the actuation system is configured to selectively facilitate the translation of the protrusion.
A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in connection with the following illustrative figures. In the following figures, like reference numbers refer to similar elements and steps throughout the figures.
Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that may be performed concurrently or in different order are illustrated in the figures to help to improve understanding of embodiments of the present invention.
The present invention is described partly in terms of functional components and various methods. Such functional components may be realized by any number of components configured to perform the specified functions and achieve the various results. For example, the present invention may employ various techniques for reducing velocity, e.g., control surfaces, protrusions, and the like, which may carry out a variety of functions. In addition, the present invention may be practiced in conjunction with any number of missiles, artillery fuzes, bombs, or other projectiles, and the system described is merely one exemplary application for the invention. Further, the present invention may employ any number of conventional techniques for firing or launching projectiles, detonating warheads, navigating, and the like, and the system described is merely one exemplary application for the invention. Various representative implementations of the present invention may be applied to any system for explosive projectiles, such as missiles, bombs, artillery shells, and/or the like. Referring now to
The casing 112 houses various elements of the projectile 100. The casing 112 may perform any appropriate functions for the application of the projectile 100, such as protecting the munition 110, propulsion system 116, and directional guidance system 118 from damage, allowing the projectile 100 to be safely handled, and providing an aerodynamic housing over the elements. The casing 112 can be made of any suitable material, such as metal, ceramic, carbon fiber, plastic or other material that sufficiently meets the requirements of a given use.
The propulsion system 116 may comprise any system that propels the projectile, for example to initiate the launch of the projectile 100 and/or propel the projectile 100 following initial launch or firing. In one embodiment, the propulsion system provides substantially longitudinal force, such as a conventional rear-mounted rocket motor. The propulsion system 116 may provide any appropriate forces to the projectile 100, such as lateral forces for guidance or longitudinal force for range control. For example, the propulsion system 116 may comprise a conventional rocket motor, or may be omitted altogether.
The fuze 114 selectively detonates the munition 110. The fuze 114 may ignite or otherwise cause detonation of the munition 110 in any appropriate manner, e.g., a timed fuze, contact detonator, proximity fuze, altitude fuze, or remote detonation. In the present embodiment, the fuze 114 comprises a multi-option fuze, such as a conventional fuze used in 105 mm and 155 mm artillery applications that screws into a fuze well formed in the casing 112.
The directional guidance system 118 steers the projectile 100, for example to guide the projectile 100 and/or increase accuracy. The directional guidance system 118 may comprise any system that facilitates altering the course of the projectile, such as tail fins, rudders, or impulse propulsion. The directional guidance system may further include other elements for guiding the projectile, such as GPS receivers, inertial guidance systems, control systems, and sensors for determining the position of the projectile 100 and/or adjusting the course of the projectile.
In the present embodiment, the directional guidance system 118 includes an air brake system 210. The air brake system 210 slows the projectile 100 in response to a trigger signal or event, such as a signal that the projectile 100 may overshoot its intended target. The air brake system 210 may be configured in any manner to increase the aerodynamic drag on the projectile 100 when deployed, such as an airflow obstacle to effectively increase the frontal surface area of the projectile 100 in the free air stream or otherwise slow the projectile 100. For example, referring to
The air brake system 210 may be integrated into or otherwise attached to other elements of the projectile 100 in any location, such as the casing 112. For example, the air brake system 210 may comprise an integrated component of the projectile 100, or may be retrofitted to preexisting projectiles 100. Referring now to
The protrusions 212 selectively extend into the free air stream while the projectile 100 is in motion and may be configured in any suitable manner to effectively increase the drag on the projectile 100. For example, the protrusions 212 may include flat plates, round discs, fins, or spoilers. The protrusions 212 may also be set at any angle relative to the direction of the projectile 100 after they are extended into the air stream. For example, referring to
The protrusions 212 may comprise any suitable material for a particular projectile 100 application and/or environment. For example, the material may comprise metal, ceramic, composite material such as carbon graphite or Kevlar, or other sufficiently rigid material. In the present artillery-fired embodiment, the three air brake discs 310 comprise a heat-treated stainless steel.
The protrusions 212 may be extended from the projectile 100 in any suitable manner such as by spring tension, piston actuation, or explosive force. Deployment of the protrusions 212 may also comprise a stepped or modulated procedure, wherein the protrusions 212 are not fully deployed but instead deployed partially, such as continuously or in increments, based on the amount of velocity reduction required for the projectile 100.
The protrusions 212 may be configured in any suitable manner that allows the protrusions 212 to extend into the air stream and increase the drag on the projectile 100. The movement of each of the protrusions 212 is around at least one pivot that at least partially controls the translated movement of at least one of the protrusions 212. The pivot may be configured in any suitable manner to allow the protrusions 212 to extend outward from the projectile 100.
Referring to
Translation of the air brake discs 310 outward is accomplished by a channel beginning at the edge of the air brake discs 310. For example, referring to
In the present embodiment, the amount of rotation is controlled by an arc shaped opening on the forward disc 410, the middle disc 412, and the aft disc 414. For example, referring to
Referring to
The forward disc 410, the middle disc 412, and the aft disc 414 are further configured to allow the projectile 100 to be fully assembled and not impede the translation of the air brake discs 310. For example, referring to
The air brake discs 310 may further comprise a locking system to retain the air brake system 210. The air brake system 210 may comprise any system to retain the air brake discs 310, such as locking tabs or segmented pins. For example, in the present embodiment, the locking system comprises several small pins and notches configured into the air brake discs 310.
More specifically, referring to
The deployment system 214 maintains retention of the air brake system 210 until a command to deploy is initiated. After a command to deploy is received by the deployment system 214, it releases the air brake system 210 allowing the protrusions 212 to extend out from the projectile 100. The deployment system 214 may be configured in any way to prevent undesired movement of the protrusions 212. For example, the deployment system 214 may comprise a block that is configured to maintain system retention such as a bolt, a lock, a pin, a tab, or a movable element.
For example, referring now to
The deployment pin 424 acts as a lock on the air brake discs 310 preventing undesired rotation. The deployment pin 424 may be configured in any manner to prevent rotation. The deployment pin 424 may comprise any suitable material such as metal or plastic. For example, referring to
The actuator system 810 disengages the deployment pin 424 from the air brake discs 310. The actuator system 810 may comprise any system for disengaging the deployment pin 424 such as a spring loaded pin removal device or a system that shears off the deployment pin 424. In the present embodiment, the actuator system 810 disengages the deployment pin 424 by using a piston actuated sliding block.
Referring to now
The slider block 812 connects to the deployment pin 424 and facilitates its movement. The slider block 812 may comprise any suitable system for engaging the deployment pin 424 such as a spring loaded system or a cantilevered system. Referring to
More specifically, referring now to
The slider pin 814 connects the deployment pin 424 to the slider block 812. The slider pin 814 may comprise any system of connecting the slider pin 814 to the slider block 812. For example, referring to
The deployment pin housing 816 secures the slider block 812 and deployment pin 424 to the actuator plate assembly 822. The deployment pin housing 816 may comprise any suitable system of securing the slider block 812 and deployment pin 424 to the actuator plate assembly 822. In the present embodiment, the deployment pin housing 816 comprises a cover that is secured to the actuator plate assembly 822 and is configured such that it substantially covers the slider block 812 and deployment pin 424.
The piston actuator 818 moves the slider block 812 causing the deployment pin 424 to disengage from the forward disc 410. In the present embodiment, the piston actuator 818 engages the slider block 812 through an opening in the side of the deployment pin housing 816. The piston actuator 818 causes the slider block 812 to move laterally along the slider block recess 824. Referring to
The actuator plate assembly 822 connects the actuator system 810 to the air brake system 210. The actuator plate assembly 822 may be configured in any manner that will allow the actuator system 810 to engage the air brake system 210. The actuator plate assembly 822 may be made of any suitable material for a given projectile 100 application. For example, the material may comprise metal, ceramic, composite material such as carbon graphite or Kevlar, or other sufficiently rigid material. In the present artillery-fired embodiment, actuator plate assembly 822 is comprised of a steel alloy.
In operation, a projectile 100 is fired at a target and a precision guidance kit (PGK) acts to increase the accuracy of the projectile 100 while in flight. Increasing the accuracy of the projectile 100 may comprise any suitable method such as the use of navigational systems and control surfaces to make course corrections during flight. In the present embodiment, the air brake system 210 increases the drag on the projectile 100 to reduce the velocity affecting the ultimate range of the projectile 100.
During flight, the PGK tracks the trajectory of the projectile 100 and determines the optimum point for the air brake system 210 to be deployed. When the optimal point is reached an electronic signal is sent to the deployment system 214 and the deployment pin 424 is disengaged from the air brake system 210. The disengagement of deployment pin 424 allows centrifugal force to act on the air brake system 210 causing a set of air brake discs 310 to translate outward from the projectile 100 and into the free air stream increasing the drag.
More particularly, once the deployment pin 424 is disengaged, a forward disc 410 begins to rotate and as it does an interference pin 510 affixed to the forward disc 410 disengages from a middle disc 412 allowing it to begin rotation. As the middle disc 412 begins to rotate, an interference pin 610 affixed to the middle disc 412 disengages from an aft disc 414 allowing it to begin rotation. Centrifugal force then acts on the air brake discs 310 causing them to rotate and translate into the free air stream. The air brake discs 310 are then held in place by centrifugal force for the remainder of the projectile 100 flight.
In the foregoing specification, the invention has been described with reference to specific exemplary embodiments. Various modifications and changes may be made, however, without departing from the scope of the present invention as set forth in the claims. The specification and figures are illustrative, rather than restrictive, and modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents rather than by merely the examples described.
For example, the steps recited in any method or process claims may be executed in any order and are not limited to the specific order presented in the claims. Additionally, the components and/or elements recited in any apparatus claims may be assembled or otherwise operationally configured in a variety of permutations and are accordingly not limited to the specific configuration recited in the claims.
Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments, however, any benefit, advantage, solution to problem or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components of any or all the claims.
As used herein, the terms “comprise”, “comprises”, “comprising”, “having”, “including”, “includes” or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same.
This application claims the benefit of U.S. Provisional Patent Application No. 61/054,082, filed on May 16, 2008, and incorporates the disclosure of the application by reference.
Number | Date | Country | |
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61054082 | May 2008 | US |