Low-profile wing hinge mechanism

A airborne vehicle comprising a fuselage, a folding wing-like structure which is movable from a stowed position to a deployed position, and a hinge mechanism which couples the folding wing-like structure to the fuselage in a manner so that the folding wing-like structure displaces and rotates during movement from the stowed position to the deployed position. The hinge mechanism is housed within an outer mold line of the fuselage and folding wing-like structure to decrease the signature of the airborne vehicle.

BACKGROUND

This disclosure generally relates to folding wing-like structures for airborne vehicles such as missiles, glide bombs and unmanned aerial vehicles.

Many missiles utilize wings or stabilizers (e.g., control fins) for stabilizing and guiding the missile during flight. Missiles are frequently stored and launched from tubular launchers, and may be deployed from aircraft, ships or land vehicles, where storage space is limited. Under such circumstances it is necessary to minimize the space required for storage of the missile prior to launch, and fixed wings substantially increase the storage space requirements.

In view of the foregoing, various folding wing-like structures have been proposed for missiles, which structures are initially retracted into a storage position and can be deployed automatically during flight of the missile to swing out from the missile body. Some folding wing-like structures currently incorporated in missiles use hinges to pivotably couple the folding wing to the missile body. However, the known wing hinge mechanisms are large and exceed the outer mold line (OML) of the wing/fuselage of the missile, creating “blisters” or other visible external features. These features increase the signature of the missile, decreasing its effectiveness.

It would be desirable to provide a low-profile internal wing deployment hinge mechanism for missiles that has a reduced signature as compared to folding wings deployed using external hinges.

SUMMARY

This disclosure is directed to a low-profile internal wing deployment hinge mechanism for airborne vehicles such as missiles, glide bombs and unmanned aerial vehicles. The hinge mechanism is housed within the OML of the wing/fuselage of the small airborne vehicle (e.g., a missile), thereby greatly reducing its signature and improving the effectiveness of the overall system. Similar hinge mechanisms can also be used to enable control fin deployment.

As used herein, the term “fin” means a small wing and the term “control fin” means a fin that is rotatable about an axis to change its angle of attack during flight. In addition, the term “wing-like structures” should be understood to refer to a category of aerodynamic flight surfaces that includes wings and fins as members.

One aspect of the subject matter disclosed in detail below is an airborne vehicle comprising a fuselage, a folding wing-like structure which is movable from a stowed position to a deployed position, and a hinge mechanism which couples the folding wing-like structure to the fuselage in a manner so that the folding wing-like structure displaces and rotates during movement from the stowed position to the deployed position, wherein the hinge mechanism is housed within the outer mold lines of the fuselage and folding wing-like structure.

In accordance with some embodiments, the hinge mechanism comprises: a first fixed linkage pin attached to the fuselage; a second fixed linkage pin attached to the folding wing-like structure; a link coupling pin; a first angled link having one end rotatably coupled to the first fixed linkage pin and an intermediate portion coupled to the link coupling pin; and a second angled link having one end rotatably coupled to the second fixed linkage pin and an intermediate portion coupled to the link coupling pin, at least one of the first and second angled links being rotatably coupled to the link coupling pin to allow relative rotation of the first and second angled links.

In accordance with one embodiment, the airborne vehicle as described in the two preceding paragraphs further comprises a first linear guide surface formed in the fuselage and a second linear guide surface formed in the folding wing-like structure. In addition, the hinge mechanism further comprises: a first link slider pin coupled to another end of the second angled link and a second link slider pin coupled to another end of the first angled link. The first link slider pin is displaceable parallel to the first linear guide surface and the second link slider pin is displaceable parallel to the second linear guide surface. The airborne vehicle may further comprise a linear actuator configured to cause the other end of the second angled link to displace relative to the fuselage when the linear actuator is actuated. The linear actuator is housed within the fuselage. In some implementations, the first and second linear guide surfaces are slots.

In accordance with one embodiment, the fuselage comprises a first cavity, and the airborne vehicle further comprises a locking block which is movable from a first position in the first cavity when the folding wing-like structure is in the stowed position to a second position partly in and partly projecting out of the first cavity when the folding wing-like structure is in the deployed position; and a spring arranged to urge the locking block toward the second position. In addition, the folding wing-like structure comprises a second cavity, and a portion of the locking block projects into the second cavity when the folding wing-like structure is in the deployed position. Preferably the second cavity has tapered surfaces and the portion of the locking block that projects into the second cavity has tapered surfaces.

Another aspect of the subject matter disclosed in detail below is an airborne vehicle comprising: a fuselage; a folding wing-like structure which is movable from a stowed position to a deployed position; a hinge mechanism which couples the folding wing-like structure to the fuselage in a manner so that the folding wing-like structure displaces and rotates during movement from the stowed position to the deployed position, wherein the hinge mechanism comprises: a first fixed linkage pin having opposed ends attached to the fuselage; a second fixed linkage pin having opposed ends attached to the folding wing-like structure; a link coupling pin; first and second angled links each having one end rotatably coupled to the first fixed linkage pin and an intermediate portion coupled to the link coupling pin; and third and fourth angled links each having one end rotatably coupled to the second fixed linkage pin and an intermediate portion coupled to the link coupling pin, wherein at least some of the first through fourth angled links are rotatably coupled to the link coupling pin to allow concurrent rotation of the first and second angled links relative to third and fourth angled links. This airborne vehicle further comprises first and second linear guide surfaces formed in the fuselage and third and fourth linear guide surfaces formed in the folding wing-like structure, wherein the hinge mechanism further comprises: a first link slider pin coupled to another end of each of the third and fourth angled links and a second link slider pin coupled to another end of each of the first and second angled links, wherein opposing ends of the first link slider pin are displaceable parallel to the first and second linear guide surfaces respectively, while opposing ends of the second link slider pin are displaceable parallel to the third and fourth linear guide surfaces respectively. In addition, the airborne vehicle may comprise a locking block that is movable from fully inside the fuselage to a position partly projecting into a cavity formed in the wing-like structure for the purpose of locking the wing-like structure in its deployed position.

A further aspect of the subject matter disclosed in detail below is an airborne vehicle comprising: a fuselage having a longitudinal axis; a first cylinder housed inside and rotatably coupled to the fuselage; a folding control fin which is movable from a stowed position to a deployed position and which is also rotatable about a lateral axis perpendicular to the longitudinal axis; a second cylinder housed inside and fixedly coupled to the folding control fin; and a hinge mechanism which couples the first and second cylinders in a manner such that the second cylinder is displaceable and rotatable relative to the first cylinder, wherein the hinge mechanism comprises: a first fixed linkage pin having opposed ends attached to the first cylinder; a second fixed linkage pin having opposed ends attached to the second cylinder; a link coupling pin; a first angled link having one end rotatably coupled to the first fixed linkage pin and an intermediate portion coupled to the link coupling pin; and a second angled link having one end rotatably coupled to the second fixed linkage pin and an intermediate portion coupled to the link coupling pin, wherein at least one of the first and second angled links is rotatably coupled to the link coupling pin to allow rotation of the first angled link relative to second angled link.

In accordance with one embodiment, the airborne vehicle described in the preceding paragraph further comprises a first linear guide surface formed in the first cylinder and a second linear guide surface formed in the second cylinder, wherein the hinge mechanism further comprises: a first link slider pin coupled to another end of the second angled link and a second link slider pin coupled to another end of the first angled link, and further wherein the first link slider pin is displaceable parallel to the first linear guide surface and the second link slider pin is displaceable parallel to the second linear guide surface. In accordance with some embodiments, the airborne vehicle further comprises a linear actuator configured to cause the other end of the second angled link to displace relative to the first cylinder when the linear actuator is actuated. This linear actuator is housed within the fuselage.

Other aspects of low-profile internal wing deployment hinge mechanisms for airborne vehicles are disclosed below.

DETAILED DESCRIPTION

Illustrative embodiments of folding wing systems are described in some detail below. However, not all features of an actual implementation are described in this specification. A person skilled in the art will appreciate that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

Although a Harpoon missile will be specifically mentioned in the following disclosure of various embodiments of folding wing systems, it should be appreciated that the disclosed embodiments are not limited in their application to Harpoon missiles, but rather can be employed on glide bombs, unmanned aerial vehicles and other types of missiles. (For the purpose of this disclosure, the term “airborne vehicle” should be construed broadly to also include missiles, glide bombs and unmanned aerial vehicles.)

FIG. 1is a diagram representing a side view of a Harpoon missile comprising a fuselage2, a plurality (i.e., four) of folding wings10, and a plurality (i.e., four) of control fins70. A hinge mechanism suitable for use with each folding wing10and each folding control fin70will be described below with reference toFIGS. 2A, 2B, and 3A-3F. A missile comprising a fuselage2, a folding wing10and a hinge mechanism configured to couple the folding wing10to the fuselage2will be described in further detail with reference toFIGS. 4-8. A missile comprising a fuselage2, a folding control fin70and a hinge mechanism configured to couple the folding control fin70to the fuselage2will be described in further detail with reference toFIGS. 9 and 10.

FIG. 2Ais a diagram representing a sectional view of portions of a fuselage2and a folding wing10of a missile in accordance with one embodiment. A hinge mechanism18couples the folding wing10to the fuselage2in a manner such that the folding wing10will displace and rotate during movement from a stowed (i.e., folded) position to a fully deployed (i.e., not folded) position. The folding wing10is shown in a fully deployed state inFIG. 2A.

As seen inFIG. 2A, the fuselage2comprises an internal upper wall4and an internal lower wall6, which define an interior space of the fuselage2. An outer mold line of the fuselage2is not shown inFIG. 2A. The outer mold line of the folding wing10is defined in part by an external upper wall12and an external lower wall14, which further define an interior space of the folding wing. One portion of the hinge mechanism18is disposed within the fuselage interior space, while another portion of the hinge mechanism18is disposed within the folding wing interior space. Because the hinge mechanism18resides in interior spaces, it does not extend beyond the outer mold line of the fuselage2or the outer mold line of the folding wing10.

Still referring toFIG. 2A, the hinge mechanism18in accordance with one embodiment comprises: a first fixed linkage pin28having opposing ends attached to respective portions of the fuselage2(not shown); a second fixed linkage pin32having opposing ends attached to respective portions of the folding wing10(not shown); a link coupling pin24; a first angled link20having one end rotatably coupled to the first fixed linkage pin28and an intermediate portion coupled to the link coupling pin24; and a second angled link22having one end rotatably coupled to the second fixed linkage pin32and an intermediate portion coupled to the link coupling pin24, at least one of the intermediate portions of the first and second angled links20and22being rotatably coupled to the link coupling pin24to allow relative rotation of the first and second angled links20and22.

Still referring toFIG. 2A, the first fixed linkage pin28and a bearing (not shown) of the first angled link20form a first revolute joint; the second fixed linkage pin32and a bearing (not shown) of the second angled link22form a second revolute joint; and the link coupling pin24and a bearing of either one or both of the first and second angled links20and22form a third revolute joint. In accordance with an alternative embodiment, one or both of the first and second angled links20and22could be rotatably coupled to the link coupling pin24without using a bearing since the missile is used one time and the risk of binding is small for single-use items. The link coupling pin24may be configured to shear in the event that the first and second angled links20and22become jammed during deployment, thereby unjamming the hinge mechanism18.

In addition, the hinge mechanism18further comprises: a first link slider pin26coupled to another end of the second angled link22; a second link slider pin30coupled to another end of the first angled link20; an up lock pin34translatably coupled to the second angled link22; and a down lock pin36translatably coupled to the second angled link22.

The up lock pin34, when inserted in a respective hole in the fuselage, locks the folding wing10in its stowed position. Up lock pins may be provided on both sides of the hinge mechanism18. The up lock pins can be withdrawn simultaneously from their respective holes by a linear actuator (not shown), thereby releasing the folding wing10for deployment. Preferably, the up lock pins are electrically actuated so that they can unlock at the correct time. They could also be connected to the linear actuator38if one were to use a single motor to drive both the up lock pins and the second angled link22using a linkage or gear system.

The down lock pin36, when inserted in a respective hole in the fuselage, locks the folding wing10in its fully deployed position. Down lock pins may be provided on both sides of the hinge mechanism18. The down lock pins can be inserted simultaneously into their respective holes by a linear actuator (not shown), thereby locking the folding wing10in a fully deployed position. Preferably, each down lock pin is spring loaded or actuated using a respective pyrotechnic actuator so that it will be urged into its respective hole when the folding wing10reaches it fully deployed position.

It should be appreciated that other types of locking mechanisms can be employed. For example, the linear actuator could be designed to perform a locking function.

If analysis reveals that the down lock pins might be incapable of bearing the wing bending loads, then the down lock pins could be eliminated. Instead locking blocks of the type described below could be used to transfer the wing bending loads to the fuselage. In an alternative embodiment having locking blocks, the down lock pins could also be included for the purpose of removing load from the linear actuator for the linkage system.

Although only two angled links are shown inFIG. 2A, more than two angled links can be combined in one hinge assembly. For embodiments that employ hinge assemblies comprising multiple first angled links, each first angled link20has one end rotatably coupled to the first fixed linkage pin28and an intermediate portion coupled to the link coupling pin24. Similarly, for embodiments that employ hinge assemblies comprising multiple second angled links, each second angled link22has one end rotatably coupled to the second fixed linkage pin32and an intermediate portion coupled to the link coupling pin24. The intermediate portions of either the first angled links or the second angled links (or both) are rotatably coupled to the link coupling pin24to allow relative rotation of the first and second angled links20and22.

In addition, it should be appreciated that opposing ends of the first fixed linkage pin28are attached to the fuselage2, while opposing ends of the second fixed linkage pin32are attached to the folding wing10. In contrast, opposing ends of the link coupling pin24can have a length shorter than the lengths of first and second fixed linkage pins28and32because the function of the link coupling pin24is to rotatably couple the angled links to each, not couple the hinge mechanism17to either the fuselage2or the folding wing10.

The fuselage2further comprises a first pair of linear guide plates which are disposed on the opposite sides of the hinge mechanism18.FIG. 2Ashows one such linear guide plate8(disposed parallel with internal top wall4and internal bottom wall6of the fuselage2) when viewed from the side; the other linear guide plate of the first pair is not shown inFIG. 2A. The bottom surfaces of the first pair of linear guide plates block upward vertical movement of the opposing ends of the first slider pin26attached to the other end of the second angled link22. Similarly, the folding wing10further comprises a second pair of linear guide plates which are likewise disposed on opposite sides of the hinge mechanism18.FIG. 2Ashows one such linear guide plate16(disposed parallel with external top wall12and external bottom wall14of the folding wing10) when viewed from the side; the other linear guide plate of the second pair is not shown inFIG. 2A(but see linear guide plates16aand16bshown inFIG. 4). The bottom surfaces of the second pair of linear guide plates block upward vertical movement of the opposing ends of a second slider pin30attached to the other end of the first angled link20.

To clarify the structure depicted inFIG. 2A, it should be understood that respective projecting portions of the first and second link slider pins26and30extend into the page and beyond the plane in which the second angled link22rotates. Likewise the linear guide plates8and16are situated behind the plane in which the second angled link22rotates, but respectively overlying the projecting portions of the first and second link slider pins26and30.

FIG. 4shows an end view of a hinge mechanism18having four first angled links20a-20dand four second angled links22a-22d(the latter being interleaved with the former) when viewed from the folding wing side. To avoid clutter in the drawing, only second slider pin30and second linkage pin32are shown inFIG. 4. Each of the first angled links20a-20dis coupled to the second slider pin30, as indicated by dashed lines inFIG. 4. In the view as seen inFIG. 4, the upper portions of each of the first angled links20a-20dare behind and not coupled to the second fixed linkage pin32. In addition, each of the second angled links22a-22dis rotatably coupled to the second fixed linkage pin32, as indicated by dashed lines inFIG. 4. In the view as seen inFIG. 4, the lower portions of each of the second angled links22a-22dare behind and not coupled to the second slider pin30.

Still referring toFIG. 4, the folding wing10further comprises a pair of linear guide plates16aand16bwhich respectively overlie the opposing ends of the second slider pin30. The bottom surface of linear guide plate16aserves as a linear guide surface17a, while the bottom surface of linear guide plate16bserves as a linear guide surface17b. When the second slider pin30is displaced upward, one end of second slider pin30will contact linear guide surface17aand the other end of second slider pin30will contact linear guide surface17b. The linear guide surfaces17aand17bcan be positioned at a height above the external bottom wall14of folding wing10such that they guide the opposing ends of the second slider pin30to move linearly and parallel to the external bottom wall14of the folding wing10. Similarly, the pair of linear guide plates attached to the fuselage2(i.e., linear guide plate8shown and a similar linear guide plate not shown inFIG. 2A) guide the opposing ends of the first slider pin26to move linearly and parallel to the internal bottom wall6of the fuselage2.

Referring again toFIG. 2A, the missile further comprises a linear actuator38which is coupled to one end of the second angled link22. The linear actuator38is housed inside the fuselage2.FIG. 2Ashows the folding wing10fully deployed. The linear actuator38is shown in its retracted state following activation. Retraction of the linear actuator38causes the coupled end of the second angled bracket22to move from right to left, which in turn causes the folding wing10to rotate and displace from a folded position to the fully deployed position seen inFIG. 2A. During retraction of the linear actuator38, the first slider pin26moves parallel to linear guide plate8, while the second slider pin30moves parallel to linear guide plate16.

FIG. 2Bis a diagram showing a fuselage2, a folding wing10and a hinge mechanism18in accordance with an alternative embodiment. The embodiment depicted inFIG. 2Bdiffers from the embodiment depicted inFIG. 2Ain the following respects. First, the linear guide plate8seen inFIG. 2Ais replaced by a slotted vertical wall64having a slot72(seeFIG. 2B) which serves as a linear guide surface that guides linear movement of the first slider pin26parallel with the internal bottom wall6of the fuselage2. Second, the linear guide plate16seen inFIG. 2Ais replaced by a slotted vertical wall66(seeFIG. 2B) having a slot74which serves as a linear guide surface that guides linear movement of the second slider pin30parallel with the external bottom wall14of the folding wing10. Since both ends of the slider pins need to be guided, the embodiment partly depicted inFIG. 2Bincorporates linear guide surfaces in the form of slots72and74on both sides of the hinge mechanism18. More specifically, the opposing ends of the first slider pin26slide in respective slots formed in a first pair of slotted vertical walls (only one of which, i.e., slotted vertical wall64having a slot72, is shown inFIG. 2B) disposed on opposite sides of the hinge mechanism18. Similarly, the opposing ends of the second slider pin30slide in respective slots formed in a second pair of slotted vertical walls (only one of which, i.e., slotted vertical wall66having a slot74, is shown inFIG. 2B) disposed on opposite sides of the hinge mechanism18.

In both of the embodiments depicted inFIGS. 2A and 2B, in response to activation of the linear actuator38, the first slider pin26will be displaced. This in turn causes the second angled link22to displace. As the second angled link22displaces, link coupling pin24and the intermediate portion of first angled link20(which is coupled to link coupling pin24) also start to move. However, the movements of link coupling pin24and the intermediate portion of first angled link20are constrained by the coupling of the other end of first angled link20to the first fixed linkage pin28on the fuselage2. As a result, link coupling pin24is constrained to travel along a circular arc centered at the axis of the first fixed linkage pin28, thereby causing the first angled link20to rotate about the first fixed linkage pin28as the first slider pin26continues to be displaced by the linear actuator38. At the same time, the second angled link22rotates and displaces. Since the end of the second angled link22is rotatably coupled to the second fixed linkage pin32and since the second fixed linkage pin32is attached to the folding wing10, the folding wing10also rotates and displaces relative to the fuselage2as the second angled link22rotates and displaces.

FIGS. 3A through 3Fare diagrams representing the kinematics of the wing hinge mechanism described in the preceding paragraph.FIG. 3Ashows the state of the hinge mechanism when the folding wing is fully deployed, whileFIG. 3Fshows the state of the hinge mechanism when the folding wing is stowed (i.e., folded).FIGS. 3B through 3Eshow intermediate states of the hinge mechanism (i.e., the folding wing is neither folded nor fully deployed). By viewingFIGS. 3A-3Fin sequence fromFIG. 3AtoFIG. 3F, the kinematics during stowing can be understood. Conversely, by viewingFIGS. 3A-3Fin reverse sequence fromFIG. 3FtoFIG. 3A, the kinematics during deployment can be understood.

For the purpose of providing one example, the kinematics of the hinge mechanism were simulated for a case in which the wing root thickness and the link lengths (i.e., the distances separating the various pins) were assumed to have specified values.FIGS. 3A-3Fshow the various deployment angles between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage as a function of the ratio (given as a percentage) of the magnitude of the linear displacement of the first slider pin26to the wing root thickness. It should be appreciated that if the links are sized differently (i.e., the distances between the pins is relatively smaller or larger), then the deployment angles will be different than those shown inFIGS. 3A-3Ffor the same percentage displacements. Also it should be understood that the simulated relationship between deployment angle and percentage displacement is a continuous function and only selected points along that curve are depicted inFIGS. 3A-3F.

In the state depicted inFIG. 3A, the displacement of the first slider pin26is 0% and the angle between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage is 180°, i.e., the folding wing is in its fully deployed position. In the state depicted inFIG. 3B, the displacement of the first slider pin26is 14.75% and the angle between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage is 166°. In the state depicted inFIG. 3C, the displacement of the first slider pin26is 29.6% and the angle between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage is 149°. In the state depicted inFIG. 3D, the displacement of the first slider pin26is 44.4% and the angle between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage is 128°. In the state depicted inFIG. 3E, the displacement of the first slider pin26is 59.25% and the angle between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage is 101°. In the state depicted inFIG. 3F(i.e., the folding wing is stowed), the displacement of the first slider pin26is 74.0% and the angle between the linear guide plate16of the folding wing and the linear guide plate8of the fuselage is 67°. Thus the difference between the angle of orientation of the folding wing in the stowed position and the angle of orientation of the folding wing in the fully deployed position is approximately 113° for this particular computer simulation.

In the frame of reference of the missile fuselage, it can be seen inFIGS. 3A-3Fthat as the first angled link20rotates about the fixed linkage pin28, the second angled link22and the linear guide plate16(which is affixed to the folding wing) each rotate and displace relative to linear guide plate8(which is affixed to the fuselage). Thus the folding wing10rotates and displaces relative to the fuselage2as it moves between its stowed and fully deployed positions.

In cases where down lock pins of the type depicted inFIGS. 2A and 2B(i.e., down lock pin36attached to the second angled link22) would provide insufficient wing bending load-bearing capacity, actuatable load-bearing locking blocks of the type depicted inFIG. 5may be provided.FIG. 5is a diagram representing a sectional view of portions of the fuselage2and folding wing10which house a spring-loaded locking block44that can be extended to lock the folding wing10in its fully deployed position in accordance with one embodiment. When the folding wing10is in its stowed position (not shown inFIG. 5), the locking block44would be disposed entirely within a first cavity45formed in the fuselage2. When the folding wing10is moved to its fully deployed position, as shown inFIG. 5, then a second cavity48formed in the folding wing10will align with the first cavity45. When the first and second cavities are aligned, the spring46will urge the locking block44forward until it reaches its final locking position seen inFIG. 5. In the final locking position, a rearward portion of the locking block44is disposed in the first cavity45while a forward portion of the locking block44projects snugly into the second cavity48. In this position, the locking block44is able to transfer wing bending load to the fuselage2. Multiple locking blocks can be provided as needed to transfer respective wing bending loads.

FIG. 6is a diagram representing an isometric view of a folding wing system comprising a trapezoidal folding wing10, first through fifth hinge assemblies52a-52ewhich couple the folding wing10to a missile fuselage (not shown inFIG. 6), and a multiplicity of locking blocks which lock the folding wing10in its fully deployed position in accordance with one embodiment. The dashed lines represent hidden structural features inside the folding wing10. For this specific application, the multiplicity of locking blocks includes first and second narrow locking blocks54aand54b, and first through fourth wide locking blocks56a-56d. More or fewer locking blocks can be used as appropriate.

InFIG. 6, the locking blocks are shown in their respective locking positions. The forward portions of narrow locking blocks54a,54band of wide locking blocks56a-56dare received in respective similarly shaped cavities (indicated by dashed lines inFIG. 6) formed in folding wing10.FIG. 7is a diagram showing a portion ofFIG. 6on a magnified scale. As indicated by dashed lines inFIG. 7, narrow locking block54aslides into a similarly shaped cavity82, while wide locking block56aslides into a similarly shaped cavity84.

For example,FIG. 8is a diagram showing a narrow locking block54ahaving a forward portion that projects into a similarly shaped cavity82formed in the folding wing10. In this example, the forward portion of the locking block54ahas upper and lower tapered surfaces58aand58b. The cavity82has respective tapered surfaces which taper at the same angles as tapered surfaces58aand58b. Preferably, the tapered surfaces58aand58bwill respectively contact the respective tapered surfaces inside cavity82, thereby facilitating the transfer of wing bending loads to the fuselage via the locking block54a. The other locking blocks and corresponding cavities formed in the folding wing10(as shown inFIG. 7) may be configured with similarly tapered surfaces.

The locking blocks can be spring loaded or extended using pyrotechnic actuation since deployment is typically a one-way single-use action. In the alternative, actuation using electric motors could be made to work if there were a reason for electric actuation.

Referring again toFIG. 7, portions of the hinge assembly52aare disposed in a cavity72formed in the folding wing10. The other hinge assemblies52b-52eseen inFIG. 6are likewise disposed in cavities having the same size and shape as cavity72seen inFIG. 7. In accordance with one embodiment, a pair of slots74aand74b, which communicate with cavity72, are formed on opposing sides of the hinge assembly52a. Slots74aand74brespectively receive the opposing ends of the second slider pin30, as previously described. Because the wing bending loads are transferred to the fuselage (not shown inFIG. 7) by the locking blocks, the opposing ends of the second slider pin30are able to “float” in the slots74aand74b.

FIG. 7Ais a diagram representing an isometric view of the hinge assembly52adepicted inFIG. 7, but on a magnified scale. In accordance with one embodiment, each of the five hinge assemblies52a-52ehas the structure depicted inFIG. 7A. That structure includes four first angled links20a-20dand four second angled links22a-22d, interleaved with each other. Each of the four first angled links20a-20dhas one end rotatably coupled to the first fixed linkage pin32(which is attached to the fuselage) and the other end coupled to the second slider pin30. Each of the four second angled links22a-22dhas one end rotatably coupled to the second fixed linkage pin28(which is attached to the folding wing) and the other end coupled to the first slider pin26. The interleaved intermediate portions of angled links20a-20dand22a-22dare rotatably coupled to the link coupling pin24.

In other embodiments, the number of first angled links in any hinge assembly can be less or more than four. Similarly, the number of second angled links in any hinge assembly can be less or more than four.

FIG. 9is a diagram representing an isometric view of a control fin10of a Harpoon missile of the type depicted inFIG. 1. The fuselage2has a longitudinal axis (not shown inFIG. 9), while the folding control fin10is movable from a stowed position to a deployed position and is also rotatable about a lateral axis perpendicular to the longitudinal axis. The cylinder68at the root of the control fin10houses a torque tube (not shown) that is used for deployment actuation. The folding control fin10can rotate about an axis of a control cylinder60which extends generally perpendicular to the longitudinal axis of the fuselage2.

The fin deployment mechanism (i.e., the torque tube inside cylinder68) and control cylinder60depicted inFIG. 9could be replaced by a cylindrical version of the wing hinge mechanism18depicted inFIG. 2A or 2B. Such a cylindrical version would be capable of both control fin deployment and active control of the angle of attack of the control fin10during flight This would both simplify the number of mechanisms required as well as make the entire system more “low profile” without any blisters, gaps, and other non-stealthy features.

FIG. 10is a diagram representing an isometric view of a cylindrical version of a wing hinge mechanism comprising: a cylinder76which is housed inside and rotatably coupled to the fuselage2; a cylinder78which is housed inside and fixedly coupled to the folding control fin10; and a hinge assembly80which couples cylinders76and78to each other. Preferably, the axis of the link coupling pin24(seeFIG. 2A) would be located where the axis of the torque tube seen inFIG. 9is located. As cylinder78rotates and displaces relative to cylinder76, the control fin10will rotate and displace relative to the fuselage2in a similar manner.

For avoidance of doubt, it should be appreciated that the hinge assembly80depicted inFIG. 10, although having fewer first angled links and fewer second angled links, may have a construction similar to that shown inFIG. 7A. Moreover, each set of first and second angled links may have the construction depicted inFIG. 2A or 2B, except in the following respects: (a) the first linkage pin28(seeFIG. 2A) will be affixed to the first cylinder76(seeFIG. 10); (b) the second linkage pin32(seeFIG. 2A) will be affixed to the second cylinder78(seeFIG. 10); (c) the first slider pin26(seeFIG. 2A) will be slidably coupled to the first cylinder76(seeFIG. 10); and (d) the second slider pin30(seeFIG. 2A) will be slidably coupled to the second cylinder78(seeFIG. 10). In addition, a first linear guide surface is formed in the first cylinder76and a second linear guide surface is formed in the second cylinder78, which linear guide surfaces guide the motion of the first and second slider pins respectively. The missile further comprises a linear actuator (not shown inFIG. 10) configured to cause the coupled ends of the second angled links to displace relative to the first cylinder76when the linear actuator is actuated. This linear actuator is housed within the fuselage2.

While folding wing systems have been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the teachings herein. In addition, many modifications may be made to adapt a particular situation to the teachings herein without departing from the essential scope thereof. Therefore it is intended that the claims set forth hereinafter not be limited to the disclosed embodiments.