GB2274904A - Deployable wing - Google Patents

Abstract

A deployable wing (1) suitable for a missile in which the deployment mechanism is contained solely within the wing root, thus requiring minimum disturbance to the missile itself. The mechanism includes a pyrotechnic actuator (12) for initiating wing deployment and a drive block (6) moveable under the action of the actuator (12). The drive block (6) carries a drive pin (7) which, in turn, is moveable within a helical channel (14) provided in a moveable portion of the wing (1) which is hinged about the wing root. The wing (1) also includes locking means for retaining the wing in a fully deployed position. Such means are located within the wing root and operable by the actuator (12) via a spring (10) and comprise a pair of interlocking wedges (8, 9). <IMAGE>

Description

DEPLOYABLE WING This invention relates to deployable wings for use with aerodynamic bodies and in particular for use with air-launched missiles.

The use of wings which are folded over a missile body prior to launch but deployed for stabilisation of the missile during flight is known. The most common method of deployment relies on the use of spring-loaded mechanisms. One problem associated with wing deployment mechanisms of this type is the lack of reliability. Often,-springs will "setS during long-term storage and thus fail to deploy properly when required to do so. Also, there is a safety risk associated with springs stored under load. Furthermore, such mechanisms can be heavy and bulky and consequently take up a significant amount of space inside the missile body.

One object of this invention is to provide a space-saving mechanism for wing deployment which has none of the disadvantages of the spring-assisted devices.

According to one aspect of the invention, a deployable wing comprises a wing root and a moveable portion rotatably mounted thereabout and a pyrotechnic actuator located within said wing root for initiating rotation of the moveable portion with respect to said root.

The use of a pyrotechnic actuator provides the high energy necessary for wing deployment in high cross-winds. Also, the instant of deployment can be readily controlled using such a device.

According to a second aspect of the invention, a deployable wing comprises a wing root and a moveable portion rotatably mounted thereabout and drive means for bringing about rotation of the moveable portion with respect to the root, in which the drive means includes a drive pin carried in the wing root and moveable within a helical channel provided in the moveable portion.

The provision of such a helical drive arrangement enables conversion of translational motion into a rotational movement.

The drive pin may be supported in a drive block which moves within a channel provided in the wing root. Motion of the drive pin may be controlled by a suitable actuating mechanism also located within the wing root. Such an actuating mechanism could take the form of a pyrotechnic actuator (or "protractor").

According to a third aspect of the invention, a deployable wing comprises a wing root and a moveable portion rotatably mounted thereabout and locking means for locking the moveable portion in a fully deployed position in which the locking means includes a pair of interlocking wedges, said wedges being carried in the wing root, a first of said wedges being co-operable with a recess provided in said moveable portion.

The first of said wedges may be driven upwards into the recess by translational movement of a second wedge which slides under the first. Movement of the second wedge during the wing deployment sequence may be controlled by actuating means located within the wing root.

According to a fourth aspect of the invention, a deployable wing comprises a wing root and a moveable portion rotatably mounted thereabout, a pyrotechnic actuator located within said wing root for initiating deployment of said wing, a drive block moveable under the action of the actuator and carrying a drive pin and located within said wing root, said drive pin being moveable within a helical channel provided in the moveable portion, and locking means located within said wing root and moveable under the action of the actuator, said locking means comprising a pair of interlocking wedges, a first of said wedges being co-operable with a recess provided in said moveable portion.

It will be appreciated from the fore-going that the deployment mechanism is conveniently located solely within the wing root instead of at least partly in the missile itself as is the case with known arrangements. Thus the invention provides a very compact arrangement requiring minimum disturbance to the missile itself.

An embodiment of the invention will now be described, by way of example only, with reference to the drawings of which; Fig. 1 is a cutaway view of a wing deployable in accordance with the invention, Fig. 2 is an exploded view of the components comprising the wing of Fig. 1, Figs. 3A-3E are schematic views illustrating the wing deployment sequence, Fig. 4 is a cross-sectional view of an aerodynamic body, incorporating four linked deployable wings of Fig. 1, and Fig 5 is a further cross-sectional view of an aerodynamic body incorporating an alternative linked arrangement of the wings of Fig. 1.

Referring to Figs. 1 and 2, a wing 1 is hinged about a wing root attachment 2. Said attachment 2 may be secured to the outer surface of a generally cylindrical aerodynamic body (not shown).

The wing root attachment 2 is provided with front and rear lugs 3 and 4 respectively which are spaced apart from one another and define a channel 5 therebetween. Located within the channel 5 is a drive block 6 which carries a drive pin 7, an upper and a lower wedge 8 and 9 respectively and a compression spring 10 located between the drive block 6 and the wedges 8 and 9. The wedges 8 and 9 are preferably made of aluminium and the upper wedge 8 carries a plastics insert 11 which is located in a recess in its upper surface. The plastic insert 11 incorporates a peg lia. Alternatively, the insert is dispensed with and a peg is formed as an integral part of the upper wedge. In this case, the peg is preferably provided with a low friction coating.

Also carried by the wing root attachment 2 and supported within an opening in the front lug 3 is a pyrotechnic protractor 12.

The wing 1 carries at its root forward and rear guide channels 14 and 15 respectively. The forward channel 14 is formed as a helical groove, the rear guide channel 15, being a circular groove. The rear channel 15 is formed in a lug 16 which also incorporates a recess 17. The forward channel 14 is shaped to receive the drive pin 7 and the rear channel is shaped to receive the peg lla.

The wing 1 is secured to the wing root attachment 2 so that the drive pin 7 sits in the helical groove 14 provided in the root of the wing 1. When the wing is fully deployed, the insert 11 and part of the upper wedge are located in the recess 17. The location of the wing 1 with respect to the wing root attachment 2 is further assisted by front and rear locating rods 18 and 19 respectively which run through corresponding channels in both the wing 1 and the attachment 2.

Operation of the mechanism from a wing stowed position to a fully deployed position will now be described with reference to Figs. 3A-3E.

Retention of the wing 1 in the stowed position (see Fig.

3A) is achieved by virtue of a detent 20 (see Fig. 1) at the start of the helical groove 14. Any manual attempt to open the wing beyond, say 15 deg., results in the drive pin 7 engaging in the detent 20 and the wing 1 locking. Furthermore, the force of the compression spring 10 is made sufficient to ensure that the drive pin 7 will not prematurely disengage from the detent 20 under the influence of vibration or gravity.

To counter the effects of tolerance and to provide a preload within the drive block mechanism, a spring loaded buffer (not shown) can, if required, be incorporated in the forward end of the drive block 6. The buffer could comprise, for example, a series of dished washers.

When the wing 1 is in the stowed position, the buffer reacts on the protractor 12 and provides a presetable preload. The buffer may also provide some degree of preload between the wing 1 and a launch tube in which the corresponding aerodynamic body may be placed.

On receipt of a firing current, the protractor 12 ejects its piston 13 which in turn, displaces the drive block 6.

Hence the drive pin 7 is released from the detent 20. As the piston 13 begins to move outwards, it pushes the drive block 6 along the channel 5, compressing the spring 10. In so doing, the drive pin 7 moves along the helical groove 14 (see Fig. 3A) and begins to deploy the wing 1, thus converting a translational motion into a rotational movement.

The angle of the helical groove 14 may be varied along the length of the groove in order to vary the efficiency of the deployment mechanism during the deployment sequence i.e. in order to match protractor performance with load.

To maximise efficiency of the helical drive mechanism (comprising the drive pin 7 and the helical groove 14), the inventor has considered different designs of drive pin 7 with the object of reducing friction and contact stress within the groove 14. To avoid high contact stress and the associated energy loss due to brinelling of the groove 14, the drive pin 7 could be shaped to key into the groove 14 and the contact area chosen to keep the bearing stress below the proof value of the material in which the groove 14 has been formed. A round drive pin 7 has been found to be satisfactory and in order to reduce friction, the pin 7 is preferably mounted in the drive block 6 in a needle roller bearing. The efficiency of the drive mechanism can be further enhanced by providing the sliding surfaces of the drive block 6 and/or channel 5 with a low-friction coating.

A further refinement to the helical drive mechanism can be made by providing the channel 5 with rails along which the drive block 6 can run. This measure prevents tipping or jamming of the block 6 within the channel 5.

Referring again to Figs. 3A - 3E, deceleration and locking of the wing 1 in the fully deployed position is achieved by means of the upper and lower wedges, 8 and 9 in conjunction with the helical drive mechanism and spring 10. Initially, when the wing is stowed, the tip of the upper wedge 8 rests on the tip of the lower wedge 9 and the root of the wing rests on the peg 11a (see Fig. 3A).

As the deployment sequence commences and the wing begins to rotate, translational movement is transmitted from the drive block 6 to the lower wedge 9 via the spring 10 which initially compresses then expands (see Figs 3B and 3C), forcing the lower wedge 9 underneath the upper wedge 8. As a result, the upper wedge 8 moves upwards allowing the peg 11a to slot into the rear guide channel 15 (Figs. 3C). The point of engagement of the peg ila is precisely defined by a cut out 15a which is a continuation of the channel 15 (see Fig 1). As the wing 1 rotates further still, the upper wedge 8 (and peg lla) continue to move upwards into the recess 17 (Fig. 3D).

Fig 3E shows the wing locked into its fully deployed position. The size and tension of the spring 10 are chosen (in relation to the mass of the wedges) so that the wing is locked (by movement of the upper wedge 8 and insert 11 into the recess 17) at the same moment that the fully deployed position is reached.

The wing 1 is prevented from moving beyond the fully deployed position or towards a stowed position due to friction between the contiguous surfaces of the upper and lower wedges 8 and 9. The angles of the contiguous surfaces are chosen so as to prevent the possibility of backdrive bearing in mind the coefficient of friction between the surfaces.

The above operation therefore ensures a fast and smooth positive engagement of the locking mechanism which meets requirements for high wing-opening rates.

In order to manually unlatch the wing from the deployed position under test conditions, access to the lower wedge 9 is achieved by providing an access channel (not shown) in the rear lug 4. A rod inserted through the channel can them be used to push the lower wedge 9 back into its initial position. To assist relocation of the upper wedge 8 and to prevent it from being dragged along with the lower wedge, the upper wedge 8 is provided with a pin 8a which locates in a cut-out 2a in the wing root attachment 2 (see Fig. 1).

In a further embodiment, there is provided a mechanism for linking several wings using a cable system. Such linked wing arrangements are useful under circumstances where cross-winds may prevent satisfactory deployment of one or more independently-operated wings. The mechanism proposed herein employs a steel or textile cable which is passed around the airframe (of the appropriate aerodynamic body) and partially wound on a drum 21 which is secured to the rear of each wing (see Fig. 2). Alternatively, the linking could be between oppositely facing wings. Figs. 4 and 5 show a missile body 22 and launch tube perimeter 23. Four wings are shown in their stowed positions 24A-24D and their deployed positions 25A-25D.

Cables 26 are wound around the drums 21 at the rear of each wing root.

Fig 4 shows the wings folded in a common direction. An advantage of this configuration is that it achieves maximum space utilisation for any given wing span. However, in the presence of cross-winds, considerable energy must be supplied to directly overcome the resistive aerodynamic loading present on two of the four wings. This problem is mitigated by employing the contra-folded arrangement of Fig.5.

In Fig 5, with the wings contra-folded as shown, the energy requirement for deployment in a cross-wind is approximately half that of the configuration of Fig 4. This is because the resistive aerodynamic loads are lower.

Furthermore, use of this (Fig 5) arrangement cancels out any deleterious torque reaction brought about by wing deployment.

Claims (8)

1. A deployable wing comprising a wing root and a moveable portion rotatably mounted thereabout and a pyrotechnic actuator located within said wing root for initiating rotation of the moveable portion with respect to said root.

2. A deployable wing comprising a wing root and a moveable portion rotatably mounted thereabout and drive means for bringing about rotation of the moveable portion with respect to the root, in which the drive means includes a drive pin carried in the wing root and moveable within a helical channel provided in the moveable portion.

3. A deployable wing comprising a wing root and a moveable portion rotatably mounted thereabout and locking means for locking the moveable portion in a fully deployed position in which the locking means includes a pair of interlocking wedges, said wedges being co-operable with a recess provided in said moveable portion.

4. A deployable wing comprising a wing root and a moveable portion rotatably mounted thereabout, a pyrotechnic actuator located within said wing root for initiating deployment of said wing, a drive block moveable under the action of the actuator and carrying a drive pin and located within said wing root, said drive pin being moveable within a helical channel provided in the moveable portion, and locking means located within said wing root and moveable under the action of the actuator, said locking means comprising a pair of interlocking wedges, a first of said wedges being co-operable with a recess provided in said moveable portion.

5. A deployable wing according to claim 4 in which translational motion of the drive block is transmitted to a second of said wedges via a compression spring.

6. An aerodynamic body incorporating a plurality of deployable wings in accordance with any preceding claim, said wings being linked via a cable passed around the body and wound on a drum incorporated within each wing.

7. A deployable wing substantially as hereinbefore described with reference to the drawings.

8. An aerodynamic body substantially as hereinbefore described with reference to the drawings.