Patent Document

This application claims priority to Great Britain Application No. 0807395.9, filed 23 Apr. 2008, the entire contents of which is hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention is concerned with a flight surface seal. More particularly, the present invention is concerned with a seal positioned between two control surface components of an aircraft to seal a variable gap therebetween. 
     BACKGROUND OF THE INVENTION 
     In aerospace design it is desirable to seal any gaps between components of flight surfaces to present a smooth surface to the passing airflow. This reduces losses and prevents undesirable fluid flow effects such as separation of the boundary layer and subsequent loss of lift. 
     Components of aircraft flight surfaces such as wings, tail planes, fins, landing gear doors and control surfaces (e.g. flaps, slats, rudders, ailerons and spoliers) tend to move in use both intentionally in response to a control input (in the case of control surfaces) and unintentionally due to thermal expansion and contraction and stresses experienced in use. 
     As such, the width of the gaps to be sealed between components varies depending on the relative position of the components. Known seal technology utilises resilient seals which are mounted to a first component to seal against a second adjacent component and resiliently deform to the seal gap as it varies. 
     Such gap width variation is observed between variable camber flaps at the trailing edge of aircraft wings. The gap width between the wing and the flap not only changes due to control input, but also changes as the wing and flap thermally expand and contract with variations in operating temperature and during the flight cycle during which a range of stresses are experienced. 
     Furthermore, the gap width can vary along the length of the gap itself (i.e. along the wing span). 
     Traditionally, such gaps are sealed with the use of unitary flexible seals mounted to a first component and abutting a second component to seal against it and thereby seal the gap. These seals need to be sufficiently flexible and resilient to maintain the sealing effect during changes in the gap width but stiff enough to prevent significant deformation under the action of the air passing over the flight surface in flight. 
     A problem with such seals is that the requirements of flexibility to account for changes in gap width and stiffness to prevent deformation under fluid loading are counteractive. As such, it is difficult to design a seal that will fulfill both requirements. 
     Furthermore, variations in seal gap along the wing span are difficult to seal effectively as unitary seals are often too laterally stiff to account for these changes. 
     Also, seals are common in which the second component slides over a seal surface. As such there needs to be a seal flange of significant width (at least as wide as the maximum gap width) which inherently decreases the structural stiffness of the seal. 
     It is an aim of the present invention to overcome or at least mitigate one or more of the above problems. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention there is provided a seal for sealing a gap between a first and a second component of an aircraft flight surface comprising a first seal body having a first sealing portion arranged to seal against the first component, wherein the first seal body is movably mounted to the second component so as to seal at least part of the gap during relative movement of the first and second components. 
     In this manner, the sealing portion provides the sealing functionality and can be as flexible as required, whereas the movably mounted seal body can provide the required stiffness and range of motion without the requirement for sliding. 
     According to a second aspect of the invention there is provided a seal for sealing a gap between a first and a second component of an aircraft flight surface comprising a first seal body having a first sealing portion arranged to seal against the first component, and a second seal body having a second sealing portion arranged to seal against one of the first and second components, wherein the first and second seal bodies are mounted so as to be movable relative to each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described with reference to the accompanying drawings in which: 
         FIG. 1  is a side schematic view of a part of an aircraft wing in a first configuration, 
         FIG. 2  is a side schematic view of a part of the aircraft wing of  FIG. 1  in a second configuration, 
         FIG. 3  is a side schematic view of a part of the aircraft wing of  FIG. 1  in a third configuration, 
         FIG. 4  is a perspective view of a part of a seal arrangement in accordance with the present invention, 
         FIG. 5  is a perspective detail view of a part of the seal arrangement of  FIG. 4 , 
         FIG. 6  is a perspective detail view of a part of the seal arrangement of  FIG. 4 , 
         FIG. 7  is a side section view of a part of the seal arrangement of  FIG. 4  in a first configuration, 
         FIG. 8  is a side section view of a part of the seal arrangement of  FIG. 4  in a second configuration, 
         FIG. 9  is a plan view of a part of the seal arrangement of  FIG. 4  in the configuration of  FIG. 7 , 
         FIG. 10  is a plan view of a part of the seal arrangement of  FIG. 4  in the configuration of  FIG. 8 , 
         FIG. 11  is a plan view of a part of the seal arrangement of  FIG. 4  in a third configuration, 
         FIG. 12  is a plan view of a part of the seal arrangement of  FIG. 4  in a fourth configuration, 
         FIG. 13  is a plan view of a part of a second seal arrangement in accordance with the present invention, 
         FIG. 14  is an end view of a third seal arrangement in accordance with the present invention in a first configuration, 
         FIG. 15  is an end view of the seal arrangement of  FIG. 14  in a second configuration, 
         FIG. 16  is an end view of the seal arrangement of  FIG. 14  in a third configuration, 
         FIG. 17  is a perspective view of a fourth seal arrangement in accordance with the present invention, 
         FIG. 18  is an end view of the seal arrangement of  FIG. 17  in a first configuration, and, 
         FIG. 19  is an end view of the seal arrangement of  FIG. 17  in a second configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring to  FIGS. 1 to 3 , a wing  100  is shown and oriented with a direction of travel D. As such, components of the wing  100  have a leading edge in direction L and a trailing edge in a direction T. 
     The wing  100  comprises a wing spar section  102  and a spoiler hinge rib  104  for mounting a spoiler (not shown) at the wing trailing edge  106 . The wing also comprises a lower flange  107 . The wing  100  comprises a flap  108  for varying the camber of the wing  100 . The flap  108  defines a lower surface  110  and a flap leading edge  112 . 
     A gap  114  of width G is defined between the foremost part of the flap leading edge  112  and the rearmost part of the flange  108 . 
     The flap  108  can be controlled by a control actuator (not shown) to vary the camber of the wing. As such the flap  108  can move between a nominal, 0 degree position ( FIG. 1 ), a −2 degree position ( FIG. 2 ) and a +4 degree position ( FIG. 3 ). As the flap  108  moves between these positions the width G of the gap  114  changes. 
     The gap G can be sealed by means of a unitary flexible sealing element  116  which is attached to the flange  107  and cantilevered to extend towards the flap  108 . The sealing element  116  seals against the flap lower surface  110  and as the flap  108  moves the lower surface  110  slides along the sealing element  116 . 
     Flexible unitary sealing elements such as element  116  may exhibit the problems described in the introduction. 
     Turning to  FIG. 4 , a seal arrangement  200  is shown mounted to a flange  207 , similar in position within a wing assembly to the flange  107 . The flange  207  has a trailing edge  208  which defines one side of the gap (not shown) between it and a flap (not shown). 
     The flange  207  comprises a first protrusion  210  having an upright portion  212  and a flange  214  extending therefrom, better seen in  FIG. 6 . The flange  207  comprises a second protrusion  216  comprising an upright portion  218  and a plate  220  extending therefrom. The first protrusion  210  and the second protrusion  216  are alternative formations and need not necessarily be used in conjunction, although this is possible. 
     The seal arrangement  200  comprises a first seal plate  222  and a second seal plate  224 . The seal plates  222 ,  224  are identical and as such the only seal plate  222  will be described in detail. 
     The first seal plate  222  comprises a plate  226  defining an elongate slot  228  extending from a leading edge  230  thereof The first seal plate  222  comprises a step formation  232  proximate a first side edge  234  adjacent the leading edge  230 . The first step formation  232  is connected to a male mating flange  236 , parallel to the plate  226  and defining the first side edge  234 . 
     Opposite to the first side edge  234  is a second side edge  238 . Proximate the second side edge  238  there is a second step formation  240  leading to a female top mating flange  242 . Furthermore the plate  226  extends beyond the second step formation  240  to form a female mating formation  244 . 
     The seal arrangement  200  is assembled by sliding the first seal plate  222  into position such that the upright portion  212  of the first protrusion  210  extending from the flange  207  is received within the slot  228  of the plate  226 , as shown in  FIG. 6 . The second seal plate can then be assembled to the flange  207  in the same manner, however the male mating flange  236  of the second seal plate  224  is received and slidable in the female mating formation  244  of the first seal plate  222 . 
     It should be noted that the flange  214  of the first protrusion  210  and the plate  220  of the second protrusion  216  retain the seal plates  222 ,  224  adjacent the flange  207 . 
     Further details of the seal arrangement  200  will be described with reference to  FIGS. 7 and 8 . 
     As shown in  FIGS. 7 and 8  the first seal plate  222  comprises a seal element  246  at its trailing edge  248 . The seal element  246  is constructed from a flexible sealing material (e.g. rubber) and is shaped to receive a leading edge  250  of an aircraft flap  252 . 
     Additionally, the first seal plate  222  comprises a spring  254  disposed between the upright portion  212  of the first protrusion  210  and the end of the slot  228 . In use, the first seal plate  222  is able to move relative to the flange  207 . As the flap  252  approaches the flange  207  the abutment between the seal element  246  and the leading edge  250  causes the first seal plate to move relative to the flange  207  and compress the spring  254 . As the flap  252  moves away from the flange  207  the spring acts to urge the first seal plate  222  against the leading edge  250  to maintain contact and ensure that the gap between the leading edge  250  and the trailing end of the flange  207  is sealed. 
     As will be noted, the amount of sliding between the seal element  246  and the leading edge  250  of the flap  252  is reduced compared to the sealing element  116 . 
     Turning to  FIG. 9 , a seal arrangement  300  is shown comprising a plurality of seal plates  302 , each identical to the seal plate  222 . Each seal plate has a seal element  308  mounted to the trailing edge thereof. The seal plates  302  are mounted to the trailing edge of a flange  304  of a wing of an aircraft (not shown). The seal plates act to seal a gap  310  of width G between the flange  304  and a flap  306 . 
     Comparing  FIGS. 9 and 10 , the flap  306  has been moved further away from the flange  304 . As such the gap  310  has grown. Each of the seal plates  302  has moved to accommodate the change in gap width G. 
     Referring to  FIG. 11 , the gap width along the wing span is no longer consistent, and the width G 1  at a first end  312  of the gap  310  is less than the width G 2  at a second end  314 . As can be seen, each of the seal plates  302  moves independently to seal the gap  310  across the span. 
     Referring to  FIG. 12 , the gap width G also varies, but non-linearly and as can be observed, the seal plates  302  move relative to the flange  304  and each other to conform to the gap  310  and maintain sealing. 
       FIG. 13  shows an alternative seal arrangement  400  similar to the seal arrangement  300  with reference numerals for common features  100  greater. Instead of individual sealing elements on each seal plate  302 , the arrangement  400  features a single elongate sealing element  450  which spans the seal plates  402  and deforms as they move individually. In this way a continuous sealing edge  452  is provided against the flap  406 . 
     Referring to  FIG. 14 , a seal arrangement  500  similar to the seal arrangement  200  is shown, with reference numerals of common features  300  greater. As can be seen, the female mating formation  544  defines a gap larger than the thickness of the male mating flange  536 . As such, the individual seal plates  522  can rotate relative to each other as the flange to which they are mounted (not shown) bends in use. 
       FIGS. 15 and 16  show the seal arrangement  500  flexing as the flange (not shown) bends. 
     Turning to  FIG. 17 , a seal arrangement  600  is shown mounted to a flange  602  of a flight surface component. The flange comprises a plurality of flange lugs  603  projecting therefrom. The seal arrangement  600  comprises a plurality of seal bodies  604 . Each seal body  604  defines a leading edge  606  on which a slot  608  is formed extending towards a trailing edge  610 . 
     The seal body  604  defines a lug  612  extending from a first side  614 . The end of the first lug  612  opposite the seal body  604  is shaped as an arc  616 . A circular bore  618  is defined at the centre of the arc  616 . The first side  614  has a concave semi-cylindrical face  615 . 
     The seal body  604  defines a slot  620  extending from a second side  622  towards the first side  614 . The lug  612  and the slot  620  are at the same position along the first and second sides respectively. The second side  622  has a convex semi-cylindrical face  623 . A bore  624  is defined at the centre of the convex semi-cylindrical face  623 . 
     To assemble the seal arrangement  600 , the lug  612  of one seal body is placed within the slot  620  of an adjacent seal body and the bores  618 ,  624  are aligned. A cylindrical shaft (not shown) is placed through the bores  618 ,  624  to provide a pinned joint between the adjacent seal bodies. 
     The seal bodies can then be mounted to the flange  602  via the flange lugs  603  which are inserted into the slots  608 . In use, the seal arrangement can therefore flex as the flange  602  flexes, as shown in  FIGS. 18 and 19 . It should be noted that a sealing element (not shown) would be positioned along the trailing edge  610  of the seal arrangement  600 . 
     Variations of the above examples fall within the scope of the present invention. 
     The seal arrangement may comprise a single elongate seal plate movably mounted to the flange. 
     The seal plate body may be manufactured from a stiff material (e.g. a composite or metal) and the seal element from a deformable sealing material e.g. rubber thus providing the required stiffness and sealing ability. Alternatively the entire seal plate may be constructed from reinforced rubber. 
     The seal element need not have an abutment formation to engage the flap—rather the seal plate could be urged by friction between a flat seal and the bottom of the flap which it seals against. 
     Preferably, the seal plates are mounted to the flange such that their travel is limited by way of a stop mechanism or abutment to prevent the seal plates from coming detached from the flange in use.

Technology Category: 7