GB2250431A - 'Aircraft seat mounting' - Google Patents

Abstract

In a seat mounting arrangement suitable for a passenger seat in a passenger aircraft, a seat pan is fixed to transverse spars 12 to which are secured first fittings 18, 20, connected with legs 14 connected in turn with a floor beam 16 secured to the floor of the aircraft passenger cabin. Each fitting 18, 20, is arranged to fit snugly around only part of the periphery of its respective spar 12 and is directly secured thereto, e.g. by rivetting. <IMAGE>

Description

Title: "Aircraft seat mounting" THIS INVENTION relates to a mounting arrangement suitable for the passenger seats of a passenger aircraft.

Conventionally, the passenger seats in passenger aircraft are secured in mounting tracks in the floor of the passenger space, each said track comprising a pair of parallel channels in said floor, said channels extending longitudinally of the aircraft fuselage. The configuration of the tracks and the seat mountings is such that the locations of the seats along the tracks can be altered or at least selected at will during fitting out of the aircraft, in accordance with the number of passenger seats to be provided and the relative spacing of the seats.

Thus, each passenger seat is secured in such a track comprising a pair of such channels and has mountings on one side engaged with one channel of the track and mountings on the other side of the seat engaged in the other channel of the track. In practice, the transverse spacing, on the floor, of the channels in such a track varies from aircraft to aircraft and consequently aircraft passenger seats, which are manufactured substantially on a volume-production basis and thus not exclusively for any particular aircraft design, are required to be adaptable to fit floor tracks of different widths.

A common mode of aircraft seat manufacture, which affords such adaptability, utilises, for each seat, a base and back structure in which the underside of the seat base has transverse round-section tubular spars which project, on each side of the seat, transversely beyond the seat base, the projecting portions of said round-section spars on the one hand supporting clamps which carry the armrests of the seat and on the other hand further clamps carried by a sub-frame or leg structure by means of which the seat is supported above the floor, such sub-frame or leg structure terminating in mountings fitted in the floor tracks.The clamps are arranged to be readily loosened and retightened, whereby adjustment of the position of such clamps along the respective spars can readily be made to suit the leg structure or sub-structure to different floor track widths, and, in principle, to adjust the transverse spacing of the armrests.

The clamps used are generally of two-part form comprising a first part connected with the respective leg structure or armrest structure and affording an open, generally semi-circular recess and a second part in the form of a yoke or cap affording a similar open generally circular recess, said yoke being connected to the first part at either end of the yoke by bolts or screws whereby the first and second parts together define a circular passage to receive the respective round tube such that the tube can be clamped in the clamp by tightening said screws to draw the yoke further towards the first part. It will be appreciated that, in some cases, the width of the floor tracks may be such that the appropriate positioning for the clamps connected with the floor mounting structure is also the appropriate spacing, for ergonomic or other considerations, for the clamps bearing the arm rests.In these circumstances, it is necessary to use different types of fittings so as to ensure that the appropriate spacing between arm rests can be maintained. This, of course, complicates fitting and means that a variety of different fittings must be provided by the manufacturer to ensure that the seats can be mounted in a variety of aircraft.

It is an object of the invention to provide a seat mounting arrangement suitable for a passenger aircraft, which avoids the above-noted disadvantage.

According to the invention there is provided a seat mounting arrangement suitable for a passenger seat in a passenger aircraft, wherein a seat pan is fixed to transverse spars to which are secured first fittings connected with floor mounting means for the seat and wherein each said first fitting is arranged to fit snugly around only part of the periphery of its respective spar and is directly secured thereto, whereby, if desired, a second fitting connected with an arm rest structure and arranged to fit snugly around the remaining part of the periphery of such spar can be fitted at the same position along the respective spar as a said first fitting, and can, alternatively, be fitted to such spar at a position offset along said spar from said first fitting.

Preferably said spars are of rectangular crosssection and each said fitting is generally U-shaped and adapted to extend over one side and no more than half-way over each of the adjoining sides of the respective said spar.

An embodiment of the invention is described below by way of example with reference to the accompanying drawings in which: FIGURE 1 is an- elevation view, as seen looking transversely of an aircraft passenger seat, illustrating the lower part of the seat pan and the manner in which the latter is connected with the aircraft floor, FIGURE 2 is a view in the direction of the arrow 2 in Figure 1, illustrating part of the mounting, FIGURE 3 is an elevation view, similar to Figure 1, but showing a variant, and partly in section, and FIGURE 4 is a view, to a larger scale, of part of the sectioned portion of Figure 3.

Referring to Figure 1, in a passenger aircraft, a passenger seat comprises a seat pan 10, only the lowermost part of which is shown in Figure 1, which is secured to, or incorporates two transverse spars 12, each extending horizontally transversely from left to right of the seat and projecting at either end from the seat pan. Arm rests (not shown) may be carried at the upper ends of brackets (not shown) secured to the projecting ends of the spars 12.

Furthermore, the spars 12 are themselves supported by a supporting structure comprising legs 14 connected at their lower ends to mounting brackets 16 secured to the floor of the passenger aircraft and at their upper ends to members 18, 20, secured to one or other of the spars 12.

Each seat has a front leg 14 on each side and a rear leg 14 on each side, the legs 14 on the left side of the seat being connected to a left-hand bracket 16 fixed in the left channel of the pair of channels (not shown) forming the track in which the seat is mounted and the legs 14 on the right hand side of the seat being connected to a right hand bracket 16 fixed in the right channel of the air of channels forming the seat mounting track. The members 18, 20, for the legs on the left are secured to the parts of the spars 12 projecting from the left side of seat pan and the members 18, 20 for the legs on the right are secured to the parts of the spars projecting from the right hand side of the seat pan.In the arrangement shown, each of the legs 14 is pivotally connected at its lower end to the respective bracket 16 and at its upper end to the respective member 18 or 20, the pivotal axes extending horizontally transversely with respect to the seat. Energy absorbing members 22, acting as diagonal braces, are pivotally connected to the brackets 16 and the members 20, the members 22 being inextensible and incompressible under normal conditions so that the seat pan is supported rigidly with respect to the floor by virtue of the diagonal bracing effect of the members 22, in the positions illustrated in solid lines in Figure 1.The members 22 are, however, designed to undergo controlled energy absorbing compression under abnormal loads, such as may occur in a crash situation, allowing energy absorbing displacement of the seat and legs to the position shown in dotted lines, thereby to reduce the forces applied to the passenger and the floor mounting brackets in a crash situation.

In adapting the seat for fitting in a particular aircraft, the positions along the spars 12 at which the members 18, 20 are secured, are selected to produce a spacing, between the two brackets 16, corresponding to the spacing between the two channels of the seat mounting track in which the seat has to be mounted in the aircraft.

Accordingly, it is possible to select, within a range of positions, the positions along the spars 12 at which the mounting members 18, 20 are secured.

The arrangement described thus far is known.

However, in the known arrangement, the spars 12 are formed of round-section tubing and the mountings to which the upper ends of the legs are attached take the form of circular clamping rings which are clamped around the spars 12. In the known arrangements, the brackets supporting the arm rests either form part of the clamps to which the legs are attached or take the form of separate clamps clamped around the spars 12 at locations spaced from the locations of the clamps to which the legs are attached, according to whether the arm rests must be aligned with or must of offset from the channels of the seat mounting track.

The illustrated seat mounting arrangement embodying the invention differs from the known arrangement in that the spars 12 are tubes of rectangular-cross-section, while the members 18, 20 comprise plates of "U" section having lugs extending from their undersides for connection with the upper ends of the legs 14 (and braces 22 in the case of members 20).

The "U"-shaped plates each afford an upwardly open rectangular channel which receives, as a snug fit, a lower part of the respective spar 12, with the base of the channel extending across the underside of the respective spar 12 and the side walls of the channel each extending half-way up the opposite side walls of the spar 12. The members 18, 20 are fixed to their respective spars 12 by bolts or rivets 26 extended through the side walls of the U-section plates and through the adjoining side walls of the respective spars 12.Thus, once the desired positions of the members 18, 20 along their respective spars 12 have been determined for fitting in any particular aircraft it is necessary to mark on the spars 12, the desired position of the holes for the bolts or rivets 26 and to form these holes appropriately. (The holes in the U-shaped plates for the bolts or rivets 26 are, of course, preferably preformed).

It will be appreciated that, since the walls of the U-shaped channels provided by the members 18, 20 extend no more than half way up the side walls of their respective spars 12, it is possible also to mount on a spar 12 an upper mounting bracket (not shown), for example for an arm rest, such bracket including a U-section plate of the same shape and dimensions as those of the members 18, 20, but inverted so as to be open downwardly, with the structure connected with the armrest proper extending upwardly from the upper side of the bracket, such upper bracket being fitted around the upper part of either spar 12 so that said inverted U-section plate extends across the top of the spar 12 and part-way down each side of the spar.Furthermore, it will be evident that such an upper mounting bracket can be so mounted directly above a member 18, 20 (in which case the lower free edges of the side walls of the upper mounting bracket closely adjoin and oppose the upper free edges of the side walls of the lower member 18, 20), or can be so mounted in a position offset along the respective spar 12, in either direction, by a desired amount. The upper mounting brackets are preferably secured to the respective spars 12 in the same way as the members 18, 20, i.e. by bolts or rivets similar to the bolts or rivets 26, extended through pre-formed holes in the side walls of the respective upper mounting brackets into the respective spars 12.

Consequently, a manufacturer of passenger seats need only provide one type of seat mounting for connecting such passenger sets with aircraft floor mounting tracks and one type of mounting for connecting arm rests to such seats, thereby simplifying manufacture and supply of appropriate parts to aircraft fitters and simplifying the fitting of such passenger seats in aircraft.

In Figure 3, parts corresponding to parts in Figures 1 and 2 have the same references.

The seat of Figure 3 differs from that of Figures 1 and 2 in the cross sectional shapes of the front and rear transverse spars, in the shapes of the corresponding members 18, 20 and in the shape of the floor beam 16, but these differences are of little significance for the purposes of the present invention. The seat arrangement of Figures 3 and 4, however, differs significantly from that of Figures 1 and 2 in that each floor bracket 16 is secured to the respective track channel at three points, rather than at two.Thus, in the arrangement of Figure 3, each floor bracket 16, in addition to being secured to its respective track channel at the front and rear ends of the bracket 16 is also secure to its track channel at a position close to the connection of the rear leg 14 with the bracket 16, by an attachment stud 30 connected with the bracket 16 proper by way of an energy absorbing connection.

The bracket 16 in this embodiment is arranged to begin deflection, in response to an upward pull, of a predetermined magnitude, applied via the rear leg 16. The last-mentioned predetermined magnitude of upward pull is selected to be within the range of magnitudes of such upward pull calculated to be encountered in the sort of crash situation which the seat is designed to cope with.

Thus, during the envisaged crash situation, as the seat moves forwards relative to the aircraft floor an upward pull is exerted on the middle part of the bracket 16 by the rear leg 14 and when this pull exceeds the predetermined value, the bracket 16 begins to bend with the middle part of the bracket deflecting upwards. Such upward movement is resisted, with a substantially constant force, by the energy absorbing studs 30. Thus some of the energy of the seat pan/passenger combination is absorbed by bending of the brackets 16, some by the studs 30 and some by shortening of the energy absorbing braces 22.

Each stud 30 may comprise, as illustrated in Figure 4, a part 32 fixed to the floor bracket 16, (for example accommodated within a bore formed in the bracket 16), and a part 34 secured to an element 36 engaged in the floor channel. The energy absorbing stud may be arranged to operate by controlled shearing of portions of one of these parts (32, 34) by the other in response to a force in excess of a predetermined value acting between these parts.

The stud 30 may, for example, be arranged to present a substantially constant resistance to upward movement of the central part of the bracket 16 relative to the floor over the relatively limited range of extension of the stud. Of course, some other form of deformable energy absorbing connection between the central part of the bracket 16 may be utilised to provide a substantially constant load resisting upward movement of the central part of the bracket 16 relative to the floor, during a crash. Such an energy absorbing connection might, for example, incorporate a deformable metal honeycomb material, known per se.

Claims (4)

1. A seat mounting arrangement suitable for a passenger seat in a passenger aircraft, wherein a seat pan is fixed to transverse spars to which are secured first fittings connected with floor mounting means for the seat and wherein each said first fitting is arranged to fit snugly around only part of the periphery of its respective spar and is directly secured thereto, whereby, if desired, a second fitting connected with an arm rest structure and arranged to fit snugly around the remaining part of the periphery of such spar can be fitted at the same position along the respective spar as a said first fitting, and can, alternatively, be fitted to such spar at a position offset along said spar from said first fitting.

2. A seat mounting arrangement according to claim 1 wherein said spars are of rectangular cross-section and each said fitting is generally U-shaped and adapted to extend over one side and no more than half-way over each of the adjoining sides of the respective said spar.

3. A seat mounting arrangement substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

4. Any novel feature or combination of features described herein.