Abstract:
Actuators already present as an integral part of the control systems of missiles and the like are used to activate and control the deployment of fins and the like without the need for separate explosively or mechanically driven fin deployment systems. Springs located in hinges on the fins accomplish the complete deployment of the fins after proper orientation by the actuators.

Description:
FIELD OF THE INVENTION 
     The present invention relates to fin deployment systems and more particularly to such systems that are useful for guiding missiles and the like. 
     BACKGROUND OF THE INVENTION 
     Existing methods for the deployment of fins from ordnance such as missiles, smart bombs or any object that is moving through the air and requires fins (wings, canards, etc.) to be initially stored in position within the cylindrical restraints of the ordnance body may use explosive bolts to release a spring that pushes the fins from a folded to an open position. Other methods have also been used including a device that holds the fins in place until exposed to a high-G load caused by some event in the launching process, such as launching from a gun barrel. The complexity of existing systems such as explosive bolts or other explosively initiated devices or even separate mechanical systems (such as separate springs, retaining clips and the like) are well known to those skilled in the art and include among others: increased safety concerns (especially with explosive bolts); reliability (moving parts in mechanical systems); longevity; stability etc. 
     It would therefore be highly desirable to have a fin deployment system that did not rely upon a separate and somewhat marginally reliable explosively or mechanically driven system to achieve deployment of fins in missiles and the like. 
     OBJECTS OF THE INVENTION 
     It is therefore one object of the present invention to provide a fin deployment system that does not rely upon a separate explosively or mechanically driven system to achieve fin deployment in missiles or the like. 
     It is another object of the present invention to provide a fin deployment system that utilizes reliable existing systems that are already an integral part of the missile, smart bomb, etc. control system. 
     SUMMARY OF THE INVENTION 
     According to the present invention, actuators already present as an integral part of the flight control systems of missiles and the like are used to activate and control the deployment of fins and other similar steering devices without the need for separate explosively or mechanically driven deployment systems. Springs located in hinges in the fins accomplish the complete deployment of the fins after proper orientation by the actuators. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially phantom view of the fin deployment system of the present invention with the fins in the folded position within the body of the missile. 
     FIG. 2 is a cross-sectional view along the line  2 — 2  of FIG.  1 . 
     FIG. 3 is a schematic side view of a single fin emerging from a missile body prior to unfolding. 
     FIG. 4 is a cross-sectional view along the line  44  of FIG.  3 . 
     FIG. 5 is a schematic side view of a single fin as it emerges from the body of a missile and begins to unfold. 
     FIG. 6 is a cross-sectional view along the line  6 — 6  of FIG.  5 . 
     FIG. 7 is a schematic side view of a single fin in the fully deployed position. 
     FIG. 8 is a cross-sectional view along the line  8 — 8  of FIG.  7 . 
     FIG. 9 is a schematic side view of an alternative embodiment of the fin deployment system of the present invention showing the fin in the partially deployed position. 
     FIG. 10 is a cross-sectional view along the line  10 — 10  of FIG.  9 . 
     FIG. 11 is an end view of a missile showing a plurality of fins deployed through the use of the fin deployment system of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Actuators are small electric motors that position the fins of a missile or the like projectile in the required position for directing the flight of the projectile. Such devices are an integral part of the control loop for missile flight. Actuators are commonly used in guidance systems of missiles, smart bombs etc. are well known in the art and already incorporated into most aircraft, aerospace and missile and bomb systems. The reliability, durability and safety of such systems are well known and well recognized by those skilled in these related arts. Such devices are commercially available from suppliers such as Moog Inc, Jamison Road, East Aurora, N.Y. 14052 and Textron Systems, 201 Lowell Street, Wilmington, Mass. 01887. 
     In the following Figures, a single fin is depicted for simplicity, however it will be readily understood that a plurality of fins  14  are generally deployed about the periphery of body  18  of a missile or the like to impart proper guidance to missile  10  in flight. In conventional practice two to four fins of the type depicted in the accompanying Figures are generally used. Such an embodiment depicting three deployed fins is shown in FIG.  11 . 
     Referring now to FIGS. 1 and 2, a missile or other similar launched device or ordnance  10  incorporates an actuator  12  and a shaft  11  to which is mounted a fin or similar steering device  14 . While actuator  12  serves to drive the movement of fin  14 , shaft  11  allows rotation of fin  14  about the various angles required for proper deployment and steering. In the pre-launch position represented in FIG. 1, fin  14  connected to actuator  12  via shaft  11  is located within a slot  16  in body  18  of missile  10 . In this position, fin  14  is stowed longitudinally within body  18  and lies parallel to the longitudinal dimension of body  18 . As can be seen in FIGS. 1 and 2, fin  14  is folded at hinge  21  proximate shaft  11  of actuator  12 . Hinge  21  actually connects fin  14  to actuator  12  via shaft  11 , and fin  14  is stowed/folded to a position perpendicular to actuator  12  and shaft  11  as depicted in FIGS. 1 and 2. In this stowed position spring  15  forces fin  14  against inner surface  17  of slot  16 . 
     As seen in FIGS. 3 and 4, upon the initiation of deployment, actuator  12  is used, via shaft  11 , to rotate fin  14  longitudinally from its completely stowed position within slot  16  in body  18  toward the exterior of body  18  in the direction shown by arrow  20 . For as long as fin  14  has not completely cleared slot  16 , (see FIGS. 7 and 8) it remains in its folded configuration due to the contact between fin  14  and inner surface  17 . It should be noted that surface  17  is preferably coated with a substance such as Teflon® or the like to render deployment of fin  14  easier. Any material that will ease the sliding of fin  14  over surface  17  may be used in this application. As activation/deployment continues, actuator  12  and shaft  11  further rotate fin  14  in the direction of arrow  20  from its fully stowed position (FIGS. 1 and 2) in slot  16 , through its partially stowed positions (FIGS. 3,  4 ,  5  and  6 ) until fin  14  clears slot  16  entirely and spring  15  causes fin  14  to deploy by rotation about hinge  21  thereby causing fin  14  to achieve its full deployment perpendicular to the longitudinal dimension of body  18 , as best seen in FIG.  8 . In this position, actuator  12  via shaft  11  can rotate fin  14 , thereby acting in its conventional manner to control the orientation of fin  14  and hence the flight path of missile  10 . This control of the orientation of the plurality of individual fins  14  (shown in FIG. 11) thus provides directional delivery of missile  10  to its appointed target. 
     In use, missile  10  is fired and upon attainment of some preset condition, number of Gs, time since firing, altitude achieved, etc. actuator  12  is activated and the rotation sequence begun. Activation of actuator  12  and shaft  11  continues until fin  14  has achieved its full deployment as shown in FIG.  8 . Actuator  12  via shaft  11  is then available to provide directional guidance to missile  10 . 
     As will be apparent to the skilled artisan, an additional combination of spring  50  and hinge  52  could also be located along the length of fin  14  at any point intermediate a first end  27  of fin  14  proximate actuator  12  and distal end  13  of fin  14  remote from actuator  12  as shown in FIGS. 9 and 10. In this configuration, fin  14  would fold at a location intermediate the first and distal ends  27  and  13  in addition to folding at the point of junction of fin  14  and actuator/shaft  12 / 11 . The spring  15 / 50 , hinge  21 / 52  combination(s) can be locked in place by means of a catch mechanism, as well known to those skilled in the art. Folding is accomplished by laying the outermost extremity of fin  14 , the distal end  13 , upon first end  27 . 
     As the invention has been described, it will be apparent to those skilled in the art that the same may be varied in many ways without departing from the spirit and scope of the invention. Any and all such modifications are intended to be included within the scope of the appended claims.