Abstract:
A missile in combination with a deployment mechanism that automatically pivots and rotates a fin from a stowed orientation to a deployed orientation. The deployment mechanism includes a spring that provides a biasing force that urges the fin to move quickly, simply and reliably from the stowed orientation to the deployed orientation. The deployment mechanism also includes one or more cams or the like for guiding the fin from the stowed orientation to the deployed orientation.

Description:
RIGHTS OF THE GOVERNMENT 
     The invention described herein was developed with Government support under Contract No. DAAH01-00-C-0107 awarded by the U.S. Department of the Army. The Government has certain rights in this invention. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to ordnance having stowable fins, and, more particularly, to a missile having a deployment mechanism for deploying the fins. 
     BACKGROUND OF THE INVENTION 
     Many types of ordnance utilize two or more protruding surfaces to affect the fluid flow around the ordnance, thereby facilitating control of its trajectory toward a target. Exemplary types of such ordnance include missiles, rockets, bombs, torpedoes and the like. 
     For example, missiles generally have an approximately cylindrical body, with at least two aerodynamic surfaces or fins that extend outwardly from the sides of the missile body to affect the aerodynamic characteristics of the missile in flight. The fins typically have an airfoil shape that is oriented edge-on or slightly inclined relative to the airflow when the missile is flying in a straight line. These fins may be, for example, static (fixed) or dynamic (selectively movable, i.e., controllable). Fixed fins generally are used to stabilize the missile during flight and do not move once fully deployed. Controllable fins (control fins) are used to control or steer the missile by selectively varying the attitude of the fins relative to the airflow under the direction of the missile&#39;s control system. 
     In many cases, the fins are stowed in a position adjacent the outside surface of or within the missile body during storage and mounting on a vehicle prior to use. In some cases, the missile is stored in a tube, canister or other protective casing, and the protective casing also may serve as a launch tube. The fins are stowed to reduce the effective diameter of the missile, permitting more missiles to be stored and/or transported in a limited space. It also reduces the likelihood of damage to the fins during storage and handling. Additionally, it allows for the maximum use of the internal space of the missile for electronic components and warheads. 
     The fins are extended from the stowed position shortly after deployment of the missile, either during mounting or launch of the missile. Various relatively complex deployment mechanisms have been developed to permit the fins to be stowed, deployed and locked into place. Control fins may further be moved (usually only rotated) by an actuator system once the control fins are deployed. 
     The mechanisms presently used to deploy the fins tend to be relatively heavy, complex and expensive to design, build and maintain. Moreover, some mechanisms occupy a relatively large volume within the missile, a significant disadvantage because of the limited space within the missile. 
     SUMMARY OF THE INVENTION 
     There is a need for a simple and reliable device to support, deploy and lock stowable ordnance fins into a deployed configuration. The present invention provides a deployment mechanism for deploying stowable fins that meets this need and provides further advantages in cost, weight and space savings. 
     More particularly, the present invention provides a missile with the deployment mechanism that automatically deploys a fin from a stowed orientation to a deployed orientation as soon as the fin is released. The deployment mechanism includes a spring that provides a biasing force that urges the fin to move quickly, simply and reliably from the stowed orientation to the deployed orientation. The deployment mechanism also includes one or more cam slots or other means for guiding the fin from the stowed orientation to the deployed orientation. 
     An exemplary deployment mechanism for the missile includes a tubular cam body that can be mounted in a cylindrical cavity in the missile body. A drive pin is connected to the cam body through the spring which biases the drive pin to the deployed orientation. The fin is connected to a cam pin that extends into cam slots in the cam body to guide the fin as it is deployed. The cam pin also interconnects the fin and the drive pin. The drive pin and the spring thus cooperate to move the fin from the stowed orientation to the deployed orientation, while the cam pin and the cam slots guide the fin as it is deployed. The cam slots may also rotate the fin as it is deployed and/or lock the fin in place. Such a deployment mechanism can be used with either a fixed fin or a dynamic control fin, in any type of ordnance having stowable fins, including the missile described herein. To simplify the description, reference herein is specifically directed to missiles, but such reference includes other types of ordnance where the description would be applicable. 
     More particularly, one aspect of the invention relates to a deployment mechanism for a missile having at least one aerodynamic fin. The deployment mechanism comprises a spring mountable in a missile for deploying the at least one fin. The deployment mechanism is operable to move the at least one fin from a stowed orientation to a deployed orientation that is different from the stowed orientation. 
     Another aspect of the invention relates to the deployment mechanism further including a tubular cam having at least one cam slot and a cam pin connected to the at least one fin. The spring is connected to the cam pin to urge the cam pin to a deployed configuration. The deployed configuration includes the at least one fin in the deployed orientation. The cam pin is movable along and guided by the at least one cam slot to pivot the at least one fin and to rotate the at least one fin from the stowed orientation to the deployed orientation. 
     To the accomplishment of the foregoing and related ends, the invention provides the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a partial and schematic perspective view of a forward section of an exemplary missile body with aerodynamic fins in a stowed configuration; 
     FIG. 2 is a partial and schematic perspective view of the missile shown in FIG. 1 with the fins in a deployed configuration; 
     FIG. 3 is a schematic cross-sectional view of a section of the missile body showing the fin and a sectioned deployment mechanism in accordance with the invention in the stowed configuration; 
     FIG. 4 is a schematic cross-sectional view of a section of the missile body showing the fin and the sectioned deployment mechanism in the deployed configuration; 
     FIG. 5 is an elevational view of a tubular cam in accordance with the invention; 
     FIG. 6 is an exploded schematic perspective view of the fin and the deployment mechanism in accordance with another embodiment of the invention; 
     FIG. 7 is a partial and schematic perspective view of the fin and the deployment mechanism of the embodiment shown in FIG. 6 in the stowed configuration partially in section; 
     FIG. 8 is a partial and schematic perspective view of the fin and the deployment mechanism of the embodiment shown in FIG. 6 in the deployed configuration partially in section; 
     FIG. 9 is a partial and schematic cross-sectional view of a fin locking mechanism provided by the present invention; 
     FIGS. 10 a - 10   e  are a sequence of schematic perspective views of the fin and the deployment mechanism shown in FIG. 6 transitioning from the stowed configuration to the deployed configuration in accordance with the invention; 
     FIGS. 11 a - 11   b  are schematic perspective views of a tubular cam in accordance with yet another embodiment of the invention; 
     FIG. 12 is a partial and schematic cross-sectional view of the fin and the deployment mechanism shown in FIGS. 10 a - 10   b  in an actuator system of the missile; 
     FIG. 13 is an exploded schematic perspective view of the fin and the deployment mechanism in accordance with still another embodiment of the invention; 
     FIG. 14 is an exploded schematic perspective view of the fin and the deployment mechanism shown in FIG. 13 from a different angle; and 
     FIG. 15 is a schematic bottom view of the fin shown in FIG.  13 . 
    
    
     In the detailed description that follows, similar components in different embodiments will have a similar reference numeral incremented by 100. For example, in a first embodiment, a cam is assigned reference number  34 . Subsequent embodiments may use reference numbers  134 ,  234 ,  334 , etc., for the cam bodies of subsequent embodiment, although the cam body may have a different configuration in the different embodiments. For the sake of brevity, in-depth descriptions of similar components may be omitted from descriptions of subsequent embodiments. 
     DETAILED DESCRIPTION 
     Referring now to the drawings, and initially to FIGS. 1 and 2, the present invention provides ordnance, such as a missile  10 , having a plurality of fins  12  for stabilizing or controlling the missile during flight. The fins  12  include at least one stowable fin  12  and a deployment mechanism  14  for moving the fin  12  from a stowed configuration (FIG. 1) to a deployed configuration (FIG. 2) so that the missile  10  can be stored or launched in a more compact configuration. The illustrated missile  10  has four fins  12  mounted to a generally cylindrical body (missile body)  16  having a longitudinal axis  18 . Although the present description refers to the missile  10  shown in the drawings, the illustrated missile  10  represents any type of ordnance that uses stowable fins and is not limited to a missile. 
     Each fin  12  has a leading edge  20  and a trailing edge  22  that bound the width of the fin  12 , and a longitudinal axis  24  that extends approximately along the length of the fin  12 . The leading edge  20  of the fin  12  preferably faces in a forward direction generally toward the leading or forward end of the missile  10  during flight. The thickness of the fin  12  is less than its width or length, and the geometry of the fin  12  is selected for its intended application. 
     In the stowed configuration shown in FIG. 1, the fins  12  lie adjacent to a surface  26  of the missile body  16 . The longitudinal axis  24  of each fin  12  approximately parallels the longitudinal axis  18  of the missile body  16 , and the leading edge  20  and the trailing edge  22  of each fin  12  face sideways to provide a compact stowed configuration wherein the missile  10  occupies a minimum volume. In the illustrated embodiment, the missile body  16  has a longitudinally extending recess  28  (FIG. 2) in its surface  26  for receiving the fin  12  in the stowed or stored configuration. With the fin  12  stowed and received in the recess  28 , an outer surface  30  (FIG. 1) of the fin  12  generally conforms to the outer surface  26  of the missile  10 . The recess  28  has a shape and size sufficient to receive the fin  12  while minimizing the volume of the missile  10  taken up by the recess  28 . In the illustrated embodiment, the recess  28  extends from an end of the fin  12  that is attached to the missile  10  toward the forward end of the missile  10 . 
     In the deployed configuration shown in FIG. 2, each fin  12  extends from the surface of the missile body  16 . The longitudinal axis  24  of the fin  12  is approximately perpendicular to the longitudinal axis  18  of the missile body  16 , and the leading edge  20  generally faces toward the forward end of the missile  10 . The fin  12  is connected to the missile body  16  through the deployment mechanism  14 , which moves the fin  12  from the stowed orientation to the deployed orientation. 
     Referring now to FIGS. 3-5, an assembly, including the fin  12  and the deployment mechanism  14 , is mounted at least partially in a cavity  32  in the missile body  16  (FIGS.  3 - 4 ). The deployment mechanism  14  includes a tubular cam  34 , a cam pin  36 , a drive spring  38 , and a drive pin  40 . The cam  34  has an internal step, shelf or ledge  42  formed by an abrupt change in its internal diameter for engaging an outer coil  44  of the drive spring  38 , which in the illustrated embodiment is a conical spring. An inner coil  46  of the drive spring  38  is connected to the drive pin  40  for applying force thereto. In the illustrated embodiment, the inner coil  46  of the drive spring  38  engages a flange portion  48  of the drive pin  40  that has a greater lateral extent than an adjacent portion of the drive pin  40 . In other words, the flange portion  48  is an annular ring or disk at one end of a smaller diameter (generally cylindrical) portion of the drive pin  40 . The drive spring  38  is mounted inside the cam  34 , interposed between the shelf  42  and the flange portion  48  of the drive pin  40  to urge or bias the drive pin  40  to the deployed orientation. 
     The drive pin  40  interconnects the drive spring  38  and the cam pin  36 . In the illustrated embodiment, a connecting portion  50  of the fin  12  has a central notch  52  at a free end thereof and the cam pin  36  is mounted to traverse the central notch  52 . The end portions of the cam pin  36  extend beyond the edges of the connecting portion  50  to engage cam slots  54 . The drive pin  40  is connected to the cam pin  36  within the central notch  52 . The cam pin  36  is rotatable with respect to at least one of the drive pin  40  and the connecting portion  50  of the fin  12  to allow the fin  12  to pivot about a longitudinal axis of the cam pin  36 . The cam pin  36  also rotates about a central axis approximately coextensive with a longitudinal axis  56  of the cam  34 . The cam pin  36  generally remains perpendicular to the longitudinal axis  56  of the cam  34  as it rotates. 
     The cam pin  36  is guided by at least one cam slot or groove  54  extending from an inner surface  58  of the cam  34  that receives and guides end portions of the cam pin  36 . In other words, the cam pin  36  acts as a follower as it traces the cam slots  54 . The cam slots  54  may extend partially or completely through the wall of the cam  34 . In the illustrated embodiment, the cam  34  has a pair of diametrically opposed and approximately helical slots  54  that guide the cam pin  36  to simultaneously rotate and translate along the longitudinal axis  56  of the cam  34  (FIG.  5 ). The shape of the cam slots  54  may be tailored to vary the path and orientation of the fin  12  as the cam pin  36  moves between the stored and deployed configurations. 
     The cam  34  guides the deployment of the fin  12  and generally is fixed in the cavity  32  against rotation in at least one direction, for example, by mating a threaded end (mounting end  60 , FIG. 5) of the cam  34  with corresponding threads in the cavity  32  (not shown). This helps to keep the cam  34  from coming loose as the fin  12  rotates into position. An opposite end of the cylindrical cam  34  (a working end  62 ), includes a pair of stepped faces  64  and  66  (hereinafter pivot face  64  and stop face  66 ) separated by two laterally spaced upright faces (one shown, FIG. 5)  68 , extending generally parallel to the longitudinal axis  56  of the cam  34 . The upright faces  68  are interposed between the pivot face  64  at the lower step and the stop face  66  at an upper step. The pivot face  64  is formed by the absence of a semi-cylindrical section at the working end  62  of the cam  34 . The cam  34  is mounted to the missile  10  such that the pivot face  64  is even with or proud of the surface of the recess  28  adjacent the cavity  32 . The stop face  66  generally extends above the missile surface  26 . As the fin  12  is moved from the stowed orientation to the deployed orientation, the fin  12  simultaneously pivots about the pivot face  64  and rotates about the longitudinal axis  56  of the cam  34 , with an end  72  of the fin  12  engaging the stop face  66  in the deployed orientation. The laterally extending end portions of the cam pin  36  travel through the cam slots  54  until the cam pin  36  reaches the deployed configuration (FIG. 2) with the lateral end portions at or near the respective ends of the cam slots  54 . The end portions of the cam slots  54  may provide positive stops for the cam pin  36  corresponding to the stored and deployed orientations of the fin  12 . In other words, the cam pin  36  may engage the ends of the cam slots  54  at the stored and deployed orientations of the fin  12 , respectively. 
     In operation, the cam slots  54  effect simultaneous rotational and pivotal movement of the fin  12  in response to the telescoping axial movement of the drive pin  40 . Retraction of the drive pin  40  by the drive spring  38  urges the cam pin  36  (in the illustrated orientation) through the cam slots  54  simultaneously rotating the cam pin  36  and the fin  12  through approximately ninety degrees (90°) from the stowed orientation (FIG. 3) to the deployed orientation (FIG.  4 ). At the same time, the connecting portion  50  of the fin  12  pivots about the pivot face  64  of the cam  34  and moves into the cam  34 . The pivot face  64  effectively functions as a fulcrum for moving the longitudinal axis  24  of the fin  12  as the fin  12  moves from an orientation substantially parallel to the longitudinal axis  18  of the missile body  16  (FIG. 3) to an orientation substantially perpendicular to the longitudinal axis  18  of the missile body  16  (FIG.  4 ). Stated another way, the cam pin  36  and the cam slots  54  translate the axial movement of the drive pin  40  into both a rotational and axial movement of the fin  12  as the cam pin  36  follows the cam slots  54 . 
     With the fin in the stowed orientation (FIG.  3 ), the drive spring  38  stores potential energy. When released, the deployment mechanism  14  simultaneously pivots and rotates the fin  12  from the stowed orientation (FIG. 3) to the deployed orientation (FIG.  4 ). The energy of the drive spring  38  drives the cam pin  36  along the longitudinal axis  56  of the cam  34  and also holds the fin  12  in the deployed orientation once deployed. Resistance created by airflow over the missile  10  also may help to deploy and to retain the fin  12  in the deployed orientation. The assembly can, of course, be modified to accommodate different sizes, configurations and types of ordnance. For example, the drive springs  38  are selected to provide the appropriate power for the size of the fins  12 . 
     A locking mechanism (not shown) may further be provided to retain the fin  12  in the deployed orientation. For example, the end portions of the cam pin  36  may be spring-loaded and outwardly biased into blind rather than through slots, and a locking detent (not shown) may be provided at an end of the cam slots  54 . The spring-loaded portions would travel along the cam slots  54  until reaching respective detents, where the end portions would extend further into the detents to lock the cam pin  36  in place. Alternatively, a bump (not shown) may be formed in the cam slots  54  over which the spring-loaded end portions would readily pass over in a first direction, but which would inhibit or prevent the spring-loaded end portions from passing in a second direction opposite the first direction. 
     A retaining mechanism (not shown) also may be used to prevent the fins  12  from moving prematurely from the stowed orientation. For example, a tab on the fin  12  may be held in place by a flange extending from the outer surface  26  of the missile body  16  to help hold the fin  12  in the stowed orientation until deployed. Locking pins (not shown) also may be used. 
     Turning to FIGS. 6-10, another assembly of a fin  112  and an alternative deployment mechanism  114  is shown. To facilitate the description, similar elements have been given similar reference numbers incremented by a factor of one hundred (100). As in the prior embodiment, the deployment mechanism  114  includes a cam  134 , a cam pin  136 , a drive spring  138  and a pivot pin  140 . The cam pin  136  spans a central notch  152  in a connecting portion  150  of the fin  112  and extends into a cam slot  154  in the wall of the cam  134 . In this embodiment, the relative positions of the drive spring  38  (FIG. 3) and the drive pin  40  (FIG. 3) of the prior embodiment have been reversed. Consequently, the drive spring  138  is interposed between the cam pin  136  and the pivot pin  140  and does not directly act on the cam body  134 . 
     The drive spring  138  is an extension spring having a loop or hook  174  at one end for engaging the cam pin  136  and a bent tab  176  at the opposite end. The pivot pin  140  in turn is held in a disk  178  at the mounting end of the cam  134 . The disk  178  may be secured to the cam  134  by corresponding threads (not shown) on the disk  178  and at the mounting end of the cam  134 . Alternatively, the disk  178  may be held against an internal shelf  142  of the cam  134  (FIG. 8) by the drive spring  138 . The cam  134  includes the internal shelf  142  that forms a stop that limits how far the disk  178  can extend into the cam  134 . The drive spring  138  holds the pivot pin  140  in the disk  178 . However, the pivot pin  140  is rotatable relative to the disk  178  about a longitudinal axis generally parallel to a longitudinal axis  156  of the cam  134  as the drive spring  138  rotates with the cam pin  136 . This arrangement further reduces the number of moving parts. Further, this arrangement provides additional force on the cam pin  136  which increases the reliability of the deployment mechanism  114 . Further still, this arrangement reduces the number of assembly steps, for example, by allowing the tab  176  of the drive spring  138  to be inserted into the pivot pin  140  from the outside of the cam  134 . 
     Turning to a detailed description of individual components, the disk  178  has a large diameter ring portion  180  and a small diameter disk portion  182  adjacent the ring portion  180 . The disk portion  182  fits inside the cam  134  and engages the internal shelf  142  when the disk  178  is fully tightened or inserted. The disk portion  182  also includes a hole or slot or other opening  184  for receiving the pivot pin  140  extending therethrough as will be explained below. The disk portion  182  is connected to an inner diameter of the ring portion  180  thereby forming a cavity inside the ring portion  180  for receiving the pivot pin  140 . 
     The pivot pin  140  is similar to the drive pin  40  shown in FIG.  3 . The pivot pin  140  has a generally cylindrical body  186  having a through hole  188  extending transverse to the longitudinal axis of the body for receipt of the tab portion  176  of the drive spring  138 . A flange portion  148  having a greater lateral extent is connected to an adjacent portion of the cylindrical body  186 . In the illustrated embodiment, the flange portion  148  is an annular ring or disk having a diameter that is larger than the opening  184  in the disk portion  182  of the disk  178 . When the pivot pin  140  is inserted through the opening in the disk  178 , the flange portion  148  is received in the cavity. When assembled, the pivot pin  140  is free to rotate about a longitudinal axis corresponding to the longitudinal axis  156  of the cam  134 . During the deployment motion, the pivot pin  140  rotates with the drive spring  138  as the drive spring  138  rotates with the cam pin  136 . 
     The drive spring  138  generally extends along a longitudinal axis perpendicular to the cam pin  136  and is telescopically received in the tubular cam  134  for extension and retraction generally parallel to the longitudinal axis  156  of the cam  134 . The drive spring  138  is an extension spring formed of several coils. On one end, the last coil forms the hook  174 . On the other end, the last coil is formed into the tab  176 . 
     The pivot pin  140  and the disk  178  anchor the drive spring  138  to the cam  134 . The drive spring  138  interconnects the pivot pin  140  and the cam pin  136  to pull the cam pin  136  through the cam slots  154  and toward the pivot pin  140 . The cam pin  136  interconnects the drive spring  138  and the fin  112 . In the illustrated embodiment, the cam pin  136  has an annular groove  190  for receiving the hook portion  174  of the drive spring  138  within the central notch  152  of the fin  112 . The annular groove  190  inhibits lateral motion of the hook  174  relative to the cam pin  136 . 
     In the illustrated embodiment, respective ends of the cam slot  154  extend in a direction substantially parallel to the longitudinal axis  156  of the cam  134  to prevent rotation of the fin  112  when the cam pin  136  is moving through that portion of the cam slot  154 . Accordingly, the cam slot  154  forces the fin  112  to pivot from the stowed orientation without rotating right away, unlike the previous embodiment. 
     At an upper or working end  162  of the cam  134 , the cam  134  has a central notch or axially relieved portion  164  formed between two laterally spaced wall sections  168  and  170 . A wedge block  192  (FIG. 6) is formed on the axially relieved portion  164  of the cam  134  between the wall sections  168  and  170 . The wedge  192  is located approximately in the center of the axially relieved portion  164  and provides a fulcrum or pivot point upon which the fin  112  initially pivots as it deploys. The wedge  192  also may be used as a stop to further prevent or minimize the fin  112  from rocking when it is in the deployed orientation. A rocking motion of the fin  112  may occur in a direction toward and away from the forward end of the missile. The wedge  192  has a narrow stop on top that engages the fin  112  during deployment. The wedge  192  has a wide base to distribute the stresses acting upon it. 
     From the axially relieved portion  164 , the wall section  170  includes a ramp  194  that spirals downward, toward the opposite end of the cam  134 , in a clockwise direction. The ramp  194  has a slope that helps to control the fin  112  as it is deployed. As the fin  112  is deployed, the end or base  172  of the fin  112  engages the ramp  194  and spirals down the slope until the fin  112  engages a stop  196  (FIG. 9) formed by an end of the opposing wall section  168 . The wall section  168  generally has a uniform height that extends above the lower end of the ramp  194  and prevents further rotation of the fin  112 . When the fin  112  engages the stop  196 , the stop  196  prevents further rotation of the fin  112 , but allows the fin  112  to move parallel to the longitudinal axis  156  of the cam  134  as will be further explained below. 
     In the illustrated embodiment, the fin  112  has a tapered tab  198  formed therein at the base of the fin  112  to help lock the fin  112  in the deployed orientation. The cam  134  further includes a slot  200  between the end of the ramp  194  and the stop  196 . The slot  200  forms part of a fin locking mechanism  202 . 
     Referring additionally to FIG. 9, the tapered tab  198  may have a raised rim  204  on a lower end thereof, the tapered tab  198  engages the fin locking mechanism  202  when the fin  112  is in the deployed configuration. The tapered tab  198  is shaped to slide into the slot  200  in a first direction, downward in the illustrated orientation, but would be inhibited or prevented from passing in a second direction opposite the first direction by the raised rim  204 . The raised rim  204  engages a corresponding raised stop  206  portion of the fin locking mechanism  202  and thus prevents the fin  112  from moving from the deployed orientation. 
     To assemble the deployment mechanism  114 , the drive spring  138  is inserted into the cam  134 . The tab  176  of the drive spring  138  is inserted through the hole  184  and into the through hole  188  of the pivot pin  140 . The pivot pin  140  is inserted into the disk  178 . The connecting portion  150  of the fin  112  is inserted into the cam  134 , the hook  174  of the drive spring  138  is placed within the notch  152  and the cam pin  136  is inserted through the connecting portion  150  and within the hook  174  of the drive spring  138  through the slots  154 . Thus, the hook  174  of the drive spring  138  is placed in the annular groove  190  of the cam pin  136  and within the notch  152  of the connecting portion  150  of the fin  112 . The disk  178  is secured in the cam  134  by the spring  138 . 
     Sequential images illustrating the deployment of the fin  112  from the stowed orientation to the deployed orientation are shown in FIGS. 10 a - 10   e . The fin  112  is shown in the stowed orientation in FIG. 10 a . As soon as the fin  112  is released, the fin  112  pivots about the wedge  192  of the axially relieved portion  164  of the cam  134 . The fin  112  then pivots approximately ninety degrees (90°) as the cam pin  136  moves within the cam slots  154  in an axial direction towards the disk  178 . Next, the laterally extending end portions of the cam pin  136  spiral through the cam slots  154  (M 2 ). The fin  112  simultaneously rotates with the cam pin  136  and moves downward into the cam  134  with the cam pin  136  (M 2 ). The end  172  of the fin  112  engages and slides along the ramp  194  of the wall section  170  until the end  172  engages the stop  196  of the wall section  168  (M 2 ). Next, the fin  112  moves in an axial direction towards the disk  178  (M 3 ). The tapered tab  198  of the fin  112  engages the fin locking mechanism  202  as the end portions of the cam pin  136  follow the end portions  208  of the slots  154 . The forward end of the fin  112  engages the stop of the wedge  192 . Thus, the fin  112  is fully deployed with a leading edge  120  facing the forward end of the missile  10  (FIG.  2 ). The fin locking mechanism  202  cooperates with the end portions  208  of the cam slots  154  and the stop of the wedge  192  to reduce the rocking of the fin  112  relative to the cam  134  during the remainder of the missile&#39;s flight. Specifically, the wedge  192  prevents the fin  112  from coming out of the locking mechanism  202  during a forward rocking motion of the fin  112 . 
     The deployment mechanism  114  shown in FIGS. 6-10 is continuously active as is the case with the deployment mechanism  14  shown in FIGS. 3 and 4. In other words, the deployment mechanism  114  continuously applies a force to the fins  112 . This urges the fins  112  to rotate from the stowed orientation to the deployed orientation. 
     During the assembly of the missile, the fins  112  are assembled in or moved to the stowed orientation and placed inside a missile launch tube, for example (not shown). As a result of placing the fins  112  in the stowed orientation, the deployment mechanism  114  continuously applies a force to the pivot pin  140  along the longitudinal axis  156  of the cam  134  toward the disk  178 . Without a locking mechanism to retain the fins  112  against the missile body  16  (FIG.  1 ), the fins  112  pivot about the axially relieved portion  164  with the distal end of the fins  112  moving away from the surface of the missile  26  (FIG. 1) and engaging an inner surface of the launch tube. The inner surface of the launch tube thus prevents the fins  112  from fully deploying. 
     During launch, the distal ends of the fins  112  engage the inner surface of the launch tube as the missile moves down the launch tube. Once the fins  112  clear the end of the launch tube, the deployment mechanisms  114  can complete the deployment of the fins  112 . The drive springs  138  urge the laterally extending end portions of cam pins  136  to move through the cam slots  154 . The fins  112  pivot and then rotate with the cam pins  136  until the bases of the fins  112  engage the fin locking mechanisms  202  and the stops of the wedges  192  of the cams  134 . Thus, the fins  112  fully deploy with the leading edges  120  facing the forward end of the missile  10  (FIG. 1) and with a longitudinal axis  124  of each fin  112  extending substantially perpendicular to the surface of the missile  26  (FIG.  2 ). 
     In an alternative embodiment, the deployment mechanism  114  may be manually or automatically activated. A retaining mechanism (not shown), such as a retaining pin, may be used to hold each fin  112  in the stowed orientation. Once the retaining pin is removed, the deployment mechanism  114  deploys the fin  112  as described in the preceding paragraph. 
     FIGS. 11 a - 11   b  and  12  show another assembly of a fin  212  and another embodiment of a deployment mechanism  214 . The deployment mechanism  214  is substantially the same as the previously described deployment mechanism  114  (FIG.  6 ). However, the deployment mechanism  214  includes an alternative cam  234 . In this embodiment, the disk  178  (FIG. 6) in the previous embodiment is incorporated into the mounting end of the cam  234  to form a single unit. In other words, the cam  234  has a closed end  278  that performs the function of the disk  178  (FIG.  6 ). The closed end  278  is in the shape of a disk and has an opening  284  therethrough. The opening  284  may be shaped as two interconnecting openings with a large diameter opening  285  near an outer edge of the closed end  278  and a small diameter opening  287  near the center of the closed end  278 . Surrounding the small diameter opening  287  is a recessed surface  289  for receiving the flange  248  of the pivot pin  240 . The closed end  278  of the cam  234  allows the final assembly to be completed completely from the exterior. This embodiment further reduces the number of parts of the deployment mechanism  214 . 
     The assembly, including the control fin  212  and the deployment mechanism  214  is shown in combination with an actuator  291  in a deployed configuration in FIG.  12 . In this embodiment, the cam  234  functions as an actuator shaft rotatably mounted to the actuator  291  for selectively rotating the control fin  212  about a longitudinal axis  256  of the cam  234  once the control fin  212  is in the deployed orientation. A missile guidance controller (not shown) selectively controls the actuator  291  to rotate the control fin  212  relative to the direction of airflow for controlled flight of the missile. 
     More specifically, as shown in FIG. 12, the cam  234  is seated in the actuator  291  within an upper bearing  293  and a lower bearing  295 . The cam  234  has threads on an outer surface of the lower end for receiving a threaded nut  297  thereon. The cam  234  also has an upper land or ridge  299 . The upper ridge  299  engages the inner race of the upper bearing  293 , and the nut  297  engages an inner race of the lower bearing  295 . As the nut  297  is tightened and torqued, the two bearings  293  and  295  are trapped across a mounting block  301  of the actuator  291  and pre-loaded to secure the cam  234  to the actuator  291 . This keeps the cam  234  from rattling around and allows the actuator  291  to rotate the cam  234 , and thus the fin  212 , at high speeds. 
     Now referring to FIGS. 13-15, yet another assembly is shown. This assembly includes a fin  312  and a deployment mechanism  314 . The fin  312  has a connecting portion  350  with a spherical attachment point  351 . The spherical attachment point  351  has a central notch  352 , which separates the spherical attachment point  351  into two generally hemispherical portions. The spherical attachment point  351  also has a through hole  353  for receiving a cam pin  336  therein. 
     The spherical attachment point  351  is manufactured to fit with a very close tolerance against the inner diameter of the cam  334 . This allows the spherical attachment point  351  to reduce the stress on the cam pin  336  as the fin  312  pivots and rotates from the stowed orientation to the deployed orientation. In particular, the spherical attachment point  351  reduces the stresses acting on the cam pin  336  in the fully deployed orientation of the fin  212  by transferring those stresses to the spherical attachment point  351 . 
     At a base  372  of the fin  312 , wedge shape protrusions extend from opposite faces of the fin  312  to form a key  398 . The key  398  cooperates with the deployment mechanism  314  to help hold the fin  312  in the deployed orientation as will be clear from the following explanation. 
     The deployment mechanism  314  is substantially similar to the previously described deployment mechanism  114  (FIG. 6) except as particularly described in the following paragraphs. The deployment mechanism  314  includes the cam  334 , the cam pin  336 , a drive spring  338 , a pivot pin  340  and a disk  378  assembled as described with respect to FIGS. 6-10. The cam  334  has a relieved portion  364  and two laterally spaced upright sections  368  and  370 . Between the laterally spaced upright sections  368  and  370  and opposite the relieved portion  364  is a keyway  355 . The keyway  355  provides additional stability for the fin  312  upon full deployment and prevents or minimizes rocking of the fin  312  during the remainder of the missile&#39;s flight. 
     The invention thus provides a simple and reliable mechanism to both hold the fins in a stowed position and to release the fins to a deployed configuration. Further, no parts of the device are shed or broken away upon deployment of the fins, thereby minimizing or eliminating the risk of injury to the launch vehicle or operator. 
     Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described components (assemblies, devices, sensors, circuits, etc.), the terms (including a reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiments of the invention. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several embodiments, such feature may be combined with one or more other features of the other embodiments as may be desired and advantageous for any given or particular application.