Abstract:
An aircraft assembly with first and second seat rails for interlocking with an aircraft seat, and a systems component mounting member interlocked with those seat rails. The mounting member has a first anchor member interlocked with the first seat rail and a second anchor member interlocked with the second seat rail. The assembly includes an aircraft systems component mounted on the mounting member. Existing seat rails or tracks of the aircraft can be used for attachment of support brackets for aircraft systems components. A novel way of using existing seat rails to provide anchorage points for systems brackets for systems components is disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to European Patent Application EP 16 178 466.5 filed Jul. 7, 2016, the entire disclosure of which is incorporated by reference herein. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to an arrangement for mounting aircraft components, in particular aircraft systems components, to aircraft seat rails. 
       BACKGROUND 
       [0003]    Aircraft cabin or cargo areas typically include parallel seat rails which are primarily used for anchoring passenger seats. The seat rails are also used for anchoring medical beds for carrying injured passengers, particularly on military transport aircraft, or cargo. The seat rails typically have standard profiles corresponding to a universal standard, such as AS33601. Thus, seats, medical beds or other equipment can be easily interchanged in accordance with the use to which the aircraft is to be put. 
       SUMMARY 
       [0004]    A first aspect of the disclosure herein provides an aircraft assembly comprising: first and second seat rails arranged to interlock with an aircraft seat; a mounting member having a first anchor member interlocked with the first seat rail and a second anchor member interlocked with the second seat rail, the mounting member having a first direction extending from the first anchor member to the second anchor member; and an aircraft systems component mounted on the mounting member. 
         [0005]    In this way, the existing seat rails (also known as seat tracks) of the aircraft can be used for attachment of support brackets for aircraft systems components such as fuel pipes. Typically, systems components within an aircraft fuselage are mounted via systems brackets that are fastened to fuselage structure such as a frame or stringer. However, it is sometimes necessary to provide aircraft systems components in parts of the fuselage of an aircraft in which it is undesirable to modify the aircraft structure in order to attach such systems brackets. For example, systems components that are only provided in some variants of an aircraft type (e.g. a fuel tanker variant of a transport aircraft), or that are retrofitted after final assembly of the aircraft. The present inventors have developed a novel way of using existing seat rails to provide anchorage points for systems brackets for such systems components. 
         [0006]    Aircraft systems components include all hardware (including wiring, pipes and other components) required for all of the various systems that contribute to operation of the aircraft. Examples of such systems include: fuel systems for transporting fuel between fuel tanks and the aircraft engines, a subset of which is fuel tanker systems which transport fuel between a fuel inlet (e.g. an in-flight refueling probe) and the fuel tanks; hydraulics for e.g. operation of flight control surfaces; electrical systems, flight control systems; bleed air systems; avionics; power plant; and ice protection systems. Thus, aircraft systems components are components that form part of an aircraft system that contributes to operation of the aircraft. Typically, aircraft systems include systems for transporting liquids (e.g. fuel or hydraulic fluid), gases (e.g. air) or electrical current (e.g. generated electricity or electrical signals). Examples of aircraft systems components suitable for use in the present disclosure include pipes or other conduits for carrying liquid (e.g. fuel or hydraulic fluid), gases (e.g. air), or electrical components (e.g. electrical wires). 
         [0007]    The aircraft assembly preferably includes a second mounting member having a first anchor member interlocked with the first seat rail at a distance from the first anchor member of the mounting member, and a second anchor member interlocked with the second seat rail at a corresponding distance from the second anchor member of the mounting member, the aircraft systems component being mounted on the second mounting member so as to extend between the mounting member and the second mounting member. Thus, an aircraft systems component, such as a fuel pipe, cable, hydraulic pipe, or other elongate component, can be supported along its length by a plurality of mounting members, without modifying the aircraft structure. 
         [0008]    The mounting member is preferably arranged such that movement of the first anchor member is substantially independent of movement of the second anchor member in at least one direction. 
         [0009]    A second aspect of the disclosure herein provides an aircraft assembly comprising: first and second seat rails arranged to interlock with an aircraft seat; and a mounting member having a first anchor member interlocked with the first seat rail and a second anchor member interlocked with the second seat rail, the mounting member having a first direction extending from the first anchor member to the second anchor member, and the mounting member being arranged such that movement of the first anchor member is substantially independent of movement of the second anchor member in at least one direction. 
         [0010]    The seat rails of an aircraft are designed to enable forces and moments applied by a passenger seat or medical bed interconnected with the seat rails to be transmitted to the fuselage structure of the aircraft, via the seat rails. However, the fuselage structure necessarily flexes and distorts during flight, e.g. as a result of aerodynamic loads on the aircraft, this distortion causing relative movement between seat rails. The present inventors have developed a mounting member in which relative movement between the seat rail connection parts (first and second anchor members) is independent in at least one direction, to prevent, or limit, any restriction of such relative movement between seat rails. The inventors have established that restriction of relative movement between seat rails is undesirable since it causes additional stresses and strains within the fuselage structure, which may cause failure of that structure. 
         [0011]    The aircraft assembly preferably includes a second mounting member having a first anchor member interlocked with the first seat rail at a distance from the first anchor member of the mounting member, and a second anchor member interlocked with the second seat rail at a corresponding distance from the second anchor member of the mounting member, the aircraft component being mounted on the second mounting member so as to extend between the mounting member and the second mounting member. 
         [0012]    The aircraft component may comprise any component housed within the aircraft, such as a passenger seat, medical bed or other item of equipment. Preferably, however, the aircraft component is an aircraft systems component, most preferably a fuel pipe of an aircraft fuel system. In embodiments in which the aircraft systems component comprises a fuel pipe, or other elongate systems component, the assembly may comprise a plurality of mounting members each supporting the fuel pipe at respective positions along its length. 
         [0013]    The mounting member is preferably arranged to permit substantially independent relative movement between the first anchor member and the second anchor member in the first direction, a second direction orthogonal to the first direction, and a third direction orthogonal to the first and second directions. Thus, substantially all restriction of relative movement between the seat rails can be prevented. 
         [0014]    The first anchor member may comprise a first joint arranged to prevent transmission of one or more moments from the mounting member to the first seat rail, the moments including: moments about the first direction, moments about a second direction orthogonal to the first direction, and moments about a third direction orthogonal to the first and second directions. In preferred embodiments the first joint is arranged to prevent transmission of moments about the first direction, moments about the second direction, and moments about the third direction from the mounting member to the first seat rail. 
         [0015]    By preventing transmission of moments about the first direction, the mounting member does not restrict relative pivoting movement with respect to the first direction between the first and second seat rails. Similarly, by preventing transmission of moments about the second direction, the mounting member does not restrict relative pivoting movement with respect to the second direction between the first and second seat rails. Finally, preventing transmission of moments about the third direction, the mounting member does not restrict relative pivoting movement with respect to the third direction between the first and second seat rails. 
         [0016]    To achieve the above functional requirements, the first joint may comprise a spherical bearing. A spherical bearing comprises a bearing that permits angular rotation (or pivoting) about a central point in three orthogonal directions. Spherical bearings can also be known as spherical plane bearings, spherical ball bushing bearings, or ball bushings, and typically comprise an inner ring with a convex outside surface and an outer ring with a correspondingly curved concave inside surface. The convex outside surface and concave inside surface are collectively considered the raceway, and slide against one another, optionally with the assistance of a lubricant, a liner (typically polytetrafluoroethylene or PTFE), or a rolling element such as a race of ball-bearings. Some spherical bearings may include a raceway comprising only one convex (toroidal) surface and one straight-sided (cylindrical) surface, the convex surface being arranged to roll relative to the straight-sided surface in order to achieve the necessary angular rotation in two of the three orthogonal directions. 
         [0017]    The first joint may alternatively comprise any other type of joint that acts as a kinematic spherical joint having three degrees of freedom. 
         [0018]    The second anchor member may comprise a second joint arranged to prevent transmission of one or more moments from the mounting member to the second seat rail, the moments including: moments about the first direction, moments about a second direction orthogonal to the first direction, and moments about a third direction orthogonal to the first and second directions. In preferred embodiments the second joint is arranged to prevent transmission of moments about the first direction, moments about the second direction, and moments about the third direction from the mounting member to the second seat rail. 
         [0019]    Like the first joint, by preventing transmission of moments about the first direction, the mounting member does not restrict relative pivoting movement with respect to the first direction between the first and second seat rails. Similarly, by preventing transmission of moments about the second direction, the mounting member does not restrict relative pivoting movement with respect to the second direction between the first and second seat rails. Finally, preventing transmission of moments about the third direction, the mounting member does not restrict relative pivoting movement with respect to the third direction between the first and second seat rails. 
         [0020]    Moreover, in embodiments in which the first and second joints are both arranged to prevent transmission of moments about the second and third directions, restriction of relative translational movement between the first and second seat rails is avoided. That is, by preventing transmission of moments about the second direction, the mounting member does not restrict relative translational movement between the first and second seat rails in the third direction. Similarly, by preventing transmission of moments about the third direction, the mounting member does not restrict relative translational movement between the first and second seat rails in the second direction. 
         [0021]    To achieve the above functional requirements, like the first joint, the second joint may comprise a spherical bearing. The second joint may alternatively comprise any other type of joint that acts as a kinematic spherical joint having three degrees of freedom. 
         [0022]    In preferred embodiments the second joint is arranged to prevent transmission of direct loads from the mounting member to the second seat rail in the first direction. In this way, relative translational movement between the first and second seat rails in the first direction is not restricted or constrained. To enable this, the second joint may be arranged to permit sliding in the first direction of the mounting member relative to the second seat rail. Preferably, the second joint comprises a pin arranged to slide within a spherical bearing. 
         [0023]    In some embodiments the mounting member comprises a third anchor member interlocked with the first seat rail or the second seat rail, the third anchor member being arranged to transmit moments about the first direction from the mounting member to the first or second seat rail, respectively. Thus, the mounting member can be restrained from pivoting about the first direction. 
         [0024]    In other embodiments the assembly includes a third seat rail and the mounting member includes a third anchor member interlocked with the third seat rail, the third anchor member being arranged to transmit movements about the first direction from the mounting member to the third seat rail. 
         [0025]    A third aspect of the disclosure herein, related to the first aspect, provides a mounting member for supporting an aircraft systems component and for interlocking with first and second aircraft seat rails that are arranged to interlock with an aircraft seat, the mounting member comprising: a first anchor member adapted or configured to interlock with the first seat rail and a second anchor member adapted or configured to interlock with the second seat rail, wherein the mounting member has a first direction extending from the first anchor member to the second anchor member; and a systems connection portion adapted or configured to support an aircraft systems component mounted on the mounting member. 
         [0026]    Movement of the first anchor member is preferably substantially independent of movement of the second anchor member in at least one direction. 
         [0027]    Optional and desirable features of the disclosure herein can be applied to any aspect of the disclosure herein, either individually or in any combination. In particular, the features described above in relation to the first and second aspects can be applied to the third aspect. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    Embodiments of the disclosure herein will now be described with reference to the accompanying drawings, in which: 
           [0029]      FIG. 1  shows a schematic view of a fuel system assembly according to an embodiment of the disclosure herein; 
           [0030]      FIG. 2  shows an isometric view of a systems mounting member suitable for the embodiment of  FIG. 1 ; 
           [0031]      FIGS. 3 and 4  show detail views of  FIG. 2 ; 
           [0032]      FIG. 5  shows a plan view of the systems mounting member of  FIG. 2 ; 
           [0033]      FIG. 6  shows a detail view of the first anchor member of  FIG. 5 ; 
           [0034]      FIG. 7  shows a detail side view (on arrow A) of the second and third anchor members of  FIG. 5 ; 
           [0035]      FIGS. 8 and 9  show a plan view and side view, respectively, of another systems mounting member suitable for the embodiment of  FIG. 1 , with the third anchor member omitted for clarity; 
           [0036]      FIGS. 10 and 11  show detail sectional views of the joints indicated by the section lines B-B and C-C, respectively, in  FIGS. 8 and 9 ; and 
           [0037]      FIGS. 12A and 12B  show isometric views of a standard seat rail and seat rail fitting. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]      FIGS. 1 through 11  illustrate embodiments of a mounting member  100  according to the disclosure herein both interlocked with ( FIGS. 1 through 7 ), and not interlocked with ( FIGS. 8 through 11 ) first  210  and second  220  seat rails. The mounting member  100  is arranged to enable direct forces (i.e. direct loads, without a moment component) to be transmitted from the mounting member  100  to the first  210  or second  220  seat rails, without constraining the first and second seat rails. That is, the mounting member  100  is arranged to prevent the transmission of any direct forces or moments (torques) from the first seat rail  210  to the second seat rail  220 , or vice versa. 
         [0039]    The mounting member  100  includes a rigid elongate beam  110  which extends between the first  210  and second  220  seat rails in the z-direction that is substantially transverse to those seat rails (the first direction). The beam  110  comprises systems connection portions  120 , each of which has fastener holes  122  through which a fuel systems bracket  310  is bolted (see  FIG. 1 ). The fuel systems brackets  310  extend around a fuel pipe  320  so as to secure the fuel pipe  320  to the mounting member  100 . Thus, a plurality of mounting members  100  arranged at spaced locations along the first  210  and second  220  seat rails together support the fuel pipe  320  (as shown in  FIG. 1 ) so that direct loads and moments are exerted by the fuel pipe  320  on to the mounting members  110 . The transmission of such direct loads and moments from the mounting members  110  to the first  210  and second  220  seat rails is controlled by the arrangement of the mounting member  100 , as discussed below. 
         [0040]    The mounting member  100  has a first anchor member  130  which is connected to a first end of the beam  110  and interlocked with the first seat rail  210 , and a second anchor member  140  which is connected to a second end of the beam  110  and interlocked with the second seat rail  220 . The mechanism for interlocking with the seat rails is in accordance with a standard connection principle, which will be described below. 
         [0041]    The connection between the first anchor member  130  and the beam  110  is via a spherical bearing  132  (best seen in  FIGS. 6 and 11 ). In the illustrated embodiments the spherical bearing  132  comprises a pin  133  supported between a pair of lugs  134  of the first anchor member  130 . The pin  133  has a central spherical (crowned, toroidal, or otherwise curved) portion which extends through a cylindrical aperture  135  of the first end of the beam  110 . To achieve rotation about the x-direction, the contacting faces of the cylindrical aperture  135  and pin  133  slide against one another. To achieve rotation (or pivoting) about the y- or z-directions, the contacting faces move relative to one another via a rolling contact. In this way, the beam  110  is able to pivot to a limited degree relative to the first anchor member  130  about the x-direction, y-direction and z-direction. 
         [0042]    The spherical bearing  132  thus permits direct forces in any direction to be transmitted from the fuel pipe  320  to the first seat rail  210 , via the beam  110 , but prevents the transmission of moments from the fuel pipe  320  to the first seat rail  210 . The spherical bearing  132  may be replaced by any joint which achieves this function, or which at least prevents the transmission of all or some moments. 
         [0043]    In other embodiments the spherical bearing  132  may have any other suitable arrangement, such as one in which the aperture  135  has a spherical (crowned, toroidal, or otherwise curved) profile and the pin  133  is cylindrical, or one in which both surfaces are spherical (crowned, toroidal, or otherwise curved) and are able to slide against one another in all three directions. 
         [0044]    The connection between the second anchor member  140  and the second seat rail  220  is via a sliding spherical bearing  142  (best seen in  FIG. 10 ). The second anchor member  140  comprises a cylindrical aperture  144  through which extends an inner ring  146  which has a spherical (crowned, toroidal, or otherwise curved) outer face  147  and a cylindrical inner face that forms a bore hole  148 . The inner ring  146  is retained within the aperture  144  in the z-direction (first direction). A cylindrical pin  149  extends from the second end of the beam  110  in the z-direction, the pin  149  passing through the bore hole  148  of the second anchor member  140  so that the pin is able to slide in the z-direction within the bore hole  148 . To achieve rotation about the z-direction, the contacting faces of the bore hole  144  and pin  149  slide against one another. To achieve rotation (or pivoting) about the x- or y-directions, the contacting faces move relative to one another via a rolling contact. In this way, the beam  110  is able to pivot to a limited degree relative to the second anchor member  140  about the x-direction, y-direction and z-direction. 
         [0045]    Thus, the slidable pin  149  of the sliding spherical bearing  142  prevents direct forces in the z-direction (first direction) from being transmitted from the fuel pipe  320  to the second seat rail  220 , via the beam  110 . The sliding spherical bearing  142  also prevents the transmission of moments from the fuel pipe  320  to the second seat rail, but permits the transmission of direct forces in the x-direction (second direction) and y-direction (third direction). 
         [0046]    The sliding spherical bearing  142  may be replaced by any joint which achieves these functions, or which at least prevents the transmission of all moments or moments about the x- and y-directions. In other embodiments the sliding pin  149  may be replaced by any other joint in the second anchor member  140 , first anchor member  130 , or beam  110  that permits relative sliding in the z-direction between the first  130  and second  140  anchor members. 
         [0047]    The mounting member  100  also includes a third anchor member  150  which interconnects the second seat rail  220  with the beam  110  via a tie rod  152 . The third anchor member  150  is interlocked with the second seat rail  220  in accordance with a standard connection principle, as described below. The tie rod  152  comprises an elongate tension rod, one end of which is connected to a grow-out portion  112  that projects in the y-direction (third direction) from the second end of the beam  110  by a first pin joint  153 . The other end of the tie rod  152  is connected to the third anchor member  150  by a second pin joint  154 . 
         [0048]    In this way, the tie rod  152  acts to prevent rotation of the beam  110  about the z-direction (first direction), by transmitting moments about the z-direction from the fuel pipe  320  to the second seat rail  220 , via the beam  110  and the third anchor member  150 . 
         [0049]    In alternative embodiments the third anchor member  150  may be omitted, and rotation of the beam  110  about the z-direction may be prevented by a keyed, or splined, connection between the pin  149  and the bore hole  148  of the second anchor member  140 , or by any other mechanism for preventing rotation of the pin  149  within the bore hole  148 . Alternatively, the joint between the first and of the beam  110  and the first anchor member  130  may be modified to prevent pivoting of the beam  110  about the z-axis relative to the first anchor member  130 . In a yet further embodiment, the third anchor member  150  may interlock with a third seat rail  230  (see  FIG. 5 ). In such embodiments the tie rod  152  may be omitted, and the third anchor member  150  may be directly connected to the beam  110 . 
         [0050]    The above-described arrangement for the mounting member  100  avoids any constraint between the first  210  and second  220  seat rails. That is, movement of the first seat rail  210  relative to the second seat rail  220  cannot cause forces to be transmitted to the second seat rail  220  via the mounting member  110 , and vice versa. The seat rails are constantly moving relative to one another during flight, as a result of changes in fuselage shape caused by aerodynamic loads amongst other things, and it is important to avoid preventing or restricting such relative movement in order to avoid inputting unwanted additional loads into the fuselage. 
         [0051]    In detail, loads cannot be transmitted between the first  210  and second  220  seat rails for the following reasons:
       Direct forces in the z-direction (first direction) cannot be transmitted because of the sliding spherical bearing  142  in which the pin  149  slides within the bore hole  148  of the second anchor member  140  in the z-direction.   Direct forces in the x- and y-directions (second and third directions, respectively) cannot be transmitted because of the spherical bearing  132  and sliding spherical bearing  142 . For example, a direct force in the x-direction applied by the first seat rail  210  to the first anchor member  130  will result in a moment about the y-direction at the second anchor member  140 , and the sliding spherical bearing  142  will prevent transmittal of that moment to the second seat rail  220 . Similarly, a direct force in the y-direction applied by the second seat rail  210  to the second anchor member  140  will result in a moment about the x-direction at the first anchor member  130 , and the spherical bearing  132  will prevent transmittal of that moment to the first seat rail.   Moments about the x- and y-directions (second and third directions, respectively) cannot be transmitted because the spherical bearing  132  and sliding spherical bearing  142  each prevent transmittal of such moments from the first  130  or second  140  anchor member, respectively, to the beam  110 .   Moments about the z-direction (first direction) cannot be transmitted because the spherical bearing  132  prevents transmittal of such moments to the beam  110  from the first seat rail  210 , via the first anchor member  130 , or transmittal of such moments to the first anchor member  130  from the second seat rail  220 , via the second anchor member  140  and beam  110 .       
 
         [0056]    In this way, the spherical bearing  132  and sliding spherical bearing  142  together prevent transmittal of direct forces and moments between the first  210  and second  22  seat rails. 
         [0057]    As discussed above, the interlocking between the first  130 , second  140  and third  150  anchor members and the first  210  or second  220  seat rails, respectively, is in accordance with a standard connection principle. The standard connection principle is controlled by universal standard AS33601, which controls the profile of seat rails used on aircraft, and standard ABS1262, which controls the profile of the interlocking parts. As shown in  FIG. 12A , the first  210  and second  220  seat rails (made in accordance with AS33601) each comprise an elongate channel with opposing overhang portions, the overhang portions having mirrored profiles such that between them they define a repeating sequence of circular apertures  230  connected by narrower straight-sided apertures  240 . Typically, the circular apertures  230  have a diameter of 19.94 mm and are spaced at a pitch of 25.4 mm between centers, while the straights-sided apertures  240  have a width of 11 mm. 
         [0058]    Standard seat rail fittings  250  (made in accordance with ABS1262) interlock with the first  210  and second  220  seat rails, as shown in  FIGS. 12A  and B. The fittings  250  each include a pair of anchor feet  252  which each comprise a truncated disc-shaped portion sized to be capable of passing through the circular aperture  230  of the rail, but not the straight-side aperture  240 . The pair of feet  252  are spaced apart from one another by the same pitch as the circular apertures, so that the fitting  250  can be interlocked with the rail by insertion of the feet  252  into the channel via a neighboring pair of circular apertures  230  and subsequent translation within the channel to a position in which removal of the feet  252  is prevented by the straight-sided apertures  240 . The right hand portion of  FIG. 12A  shows the fitting  250  during insertion, and the left hand portion shows the interlocked fitting  250  after insertion and translation. 
         [0059]    Each fitting  250  has a fastening portion  254  to which the first  130 , second  140  or third  150  anchor member is fastened in order to achieve interlocking between the respective anchor member and seat rail. A spacer  260  (see  FIG. 12A ) may be provided between the fastening portion  254  and the anchor member  130 ,  140 ,  150  in order to provide a clearance between the anchor member and the seat rail  210 ,  220 . 
         [0060]    While at least one exemplary embodiment of the invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.