Seat rail for aircraft cabin and method of manufacturing such a rail

This invention relates to a seat rail (8) for an aircraft cabin, the rail comprising a web (22) located between a top flange (24) and a bottom flange (26) with an outer surface (26a) and an inner surface (26b) fixed to the web. According to the invention, the rail is also equipped with several connection devices (20) designed for its attachment onto an aircraft structure, and being made in a single piece with the web and the top and bottom flanges, each connection device (20) having at least one through orifice (32) and projecting from the outer surface (26a).

TECHNICAL DOMAIN

This invention relates to a seat rail installed on an aircraft cabin floor in general, and a method of manufacturing such a rail.

STATE OF PRIOR ART

This type of rail is well known in prior art. Conventionally it comprises a web located between a top flange and a bottom flange, the top flange being fixed to means of fastening seats.

In a known manner, seat rails are assembled fixed to the aircraft structure below the floor, so as to provide a mechanical support on these same rails. In this respect, note that support is obtained using several attachment assemblies arranged at a spacing from each other along the rail, these assemblies usually comprising a rod connecting the aircraft structure to the web of the rail.

With reference toFIG. 1, a solution is known in prior art consisting of providing a seat rail100in which the web102is provided with several orifices104(only one is shown on the figure), these orifices being treated like rail anchor points to the extent that a pin106passes through each anchor point and also passes through a clevis-shaped end108of the connecting rod110belonging to a given attachment assembly.

It is clear from the above that the two heads112a,112bof the clevis108must be sufficiently far from each other to enable passage of the lower flange114between them, insertion of this flange114between the two heads112a,112bbeing essential to enable the orifices114a,114b, provided on these same heads, to be in line with the orifice104formed in the web102of the rail100.

The consequence of such an assembly is that the two heads112a,112bof the end of the rod in the shape of a clevis108are widely separated and at a distance from the web102, which in particular requires additional spacer plates116a,116bbetween each of the heads112a,112band this web102, with the purpose of obtaining a stack of elements in contact in pairs. With this configuration, it is then possible to correctly clamp a nut118onto the above mentioned pin106.

Although this solution does enable satisfactory installation of the rail on the aircraft structure, the associated attachment assembly for each anchor point on the rail includes a very large number of parts which is extremely disadvantageous in terms of the associated mass. In this respect, note that the above-mentioned disadvantage related to the mass of attachment assemblies is particularly restrictive because the number of anchor parts on aircraft may be extremely high, for example more than two hundred. Consequently, the same number of attachment assemblies has to be provided to assemble the seat rails on the aircraft structure.

Furthermore, the large number of parts required to make up attachment assemblies also has disadvantages such that the installation time and costs of these assemblies are very high.

Furthermore, the many metallic parts in contact are naturally subject to galvanic corrosion. This then makes it necessary to apply protecting layers during assembly, which further increase the rail installation time on the aircraft structure.

Note also that seat rails for aircraft cabins usually are long, usually more than 5 m, and possibly 10 m or more. Nevertheless, it is still necessary to install fish plates on several rails so that they jointly form segments extending over a longer length, sometimes nearly as long as the total length of the aircraft cabin. It is obvious that the parts of the attachment assembly located at the web of a rail end significantly complicate fish plating applied onto an adjacent rail.

OBJECT OF THE INVENTION

The invention is intended to propose a seat rail for an aircraft cabin, in which the design at least partially overcomes the disadvantages mentioned above related to embodiments according to prior art.

Furthermore, the purpose of this invention is to propose a method of manufacturing such a seat rail.

To achieve this, the first object of the invention is a seat rail for an aircraft cabin, the rail comprising a web located between a top flange and a bottom flange with an outer surface and an inner surface fixed to the web, said top flange also being provided with an outer surface and an inner surface fixed to the web, the outer surface of the top flange being fixed to seat attachment means. According to the invention, the rail is also equipped with several connection devices designed for its attachment onto an aircraft structure, and being made in a single piece with the web, the top and bottom flanges and the seat attachment means, each connection device having at least one through orifice projecting from the outer surface of the bottom flange.

Thus, the seat rail connection devices according to the invention form anchor points which, unlike in prior art, are located at a distance from the web of the rail since they are separated from this web by the bottom flange.

The relative advantage of such a configuration is that attachment assemblies for the installation of the rail onto the aircraft structure no longer need to cooperate with the web of the rail and consequently no longer need to be designed as a function of the geometry of the bottom flange as was the case in the past. Thus, the design of these attachment assemblies can be simplified and the number of component parts reduced such that gains in terms of cost, mass and installation time can advantageously be obtained. For example, when an attachment assembly comprises a rod with a clevis-shaped end, this end may then be installed directly on the connection device located below the web, under the bottom flange, without it being necessary to insert additional plates as shown onFIG. 1according to prior art.

Furthermore, the rail web is not intended to be fitted with parts belonging to attachment assemblies, consequently fish plating operations are easier.

Moreover, the fact that the connection devices are made in a single piece with the web and top and bottom flanges reduces the installation time of the rail on the aircraft structure, and also limits the number of parts affected by galvanic corrosion.

Furthermore, this embodiment in which the seat rail is in a single piece advantageously implies that when the connection devices are approximately in line with the web, the forces passing through these connection devices then propagate directly into the web of the rail, without any risk of deforming the free lateral ends of the bottom flange.

Preferably, each connection device is a tenon, for example designed to cooperate with a clevis of an attachment assembly connecting the rail to the aircraft structure, or a clevis, for example intended to cooperate with a tenon in such an attachment assembly. In both proposed cases, the simple installation of a pin passing through the tenon and the clevis mentioned above advantageously provides a mechanical connection between the rail and the connecting rod of a given attachment assembly.

Preferably, the top flange is provided with an outer surface and an inner surface fixed to the web, this outer surface being fixed to seat attachment means, which are preferably made in a single piece with the web, the top and bottom flanges and the connection devices.

Another object of the invention is a method of manufacturing a seat rail for an aircraft cabin like that described above and also the subject of this invention, this method comprising the following steps:manufacturing of a single piece assembly comprising the web, the top and bottom flanges, and a plate parallel to the web and projecting from the outer surface of the bottom flange; andmachining of the plate so as to eliminate portions of the plate, and to show up several connection devices.

Other advantages and characteristics of the invention will become clearer from the detailed non-limitative description given below.

DETAILED PRESENTATION OF PREFERRED EMBODIMENTS

With reference toFIG. 2, the figure briefly shows part of an aircraft (not referenced) including a cabin2, a cabin floor4, and a lower structure6of the aircraft.

The figure also shows a seat rail8according to a preferred embodiment of this invention, this rail8being arranged on the floor4. In this respect, note that a single rail8is visible onFIG. 2, but the floor8is actually fitted with several rails arranged parallel to each other, and for some along the same line as each other in order to obtain longer segments by fish plating. For example, the seat rail8may be approximately 5 m long, and may be made so as to be 10 m long or more.

The seat rail8according to the preferred embodiment described is installed rigidly on the aircraft structure6located below the floor4, through several attachment assemblies10at a spacing along rail8. For example, two attachment assemblies10directly consecutive to each other and associated with the rail8may be installed at a spacing of between about 500 and 800 mm.

As can be clearly seen onFIG. 2, each attachment assembly10comprises a fitting12installed fixed on the lower structure6, and a connecting rod14preferably arranged approximately perpendicular to the floor4, this connecting rod14having a lower end14ainstalled free to pivot on the fitting12, using a pin16.

Furthermore, the connecting rod14of the attachment assembly10also comprises a top end14bthat is fixed free to pivot using a pin18on a connection device20forming an integral part of the rail8, as will be described in more detail below.

Note that all attachment assemblies10of the seat rail8are preferably designed as has just been described, and all that changes is the length of the connecting rods14depending on the spacing between the structure6and the connection device20concerned, as can be clearly seen onFIG. 2.

Now with reference toFIG. 3, the seat rail8comprises a web22perpendicular to the floor4, this web22being located between a top flange24and a bottom flange26, the two flanges24and26being parallel to the floor4of the aircraft cabin2.

More precisely, the top flange24comprises an outer surface24aon which conventional attachment means of the seat28are provided, namely defining a groove30inside which seat legs may be installed by sliding.

The top flange24also comprises an inner surface24bfixed to the web22. In other words, the inner surface24bsets up the junction between the web22and the top flange24of the seat rail8.

Furthermore, the bottom flange26comprises an outer surface26aon which the attachment devices20are arranged that can be used as anchor points for the rail8in the structure6(only one device20being shown onFIG. 3), these devices20actually projecting from the outer surface26a. The bottom flange26also comprises an inner surface26bfixed to the web22.

A special feature of the invention is that the web22, the flanges24,26, the connection devices20and preferably also the attachment means28, jointly form an assembly made in a single piece, for example aluminium or an aluminium alloy.

As can be seen onFIG. 3, the connection devices20are located below the lower bottom flange26, since the rail8may be considered by superposition of seat attachment means28, the top flange24, the web22, the bottom flange26, and attachment devices20at a spacing from each other along this rail8, in the order given. Furthermore, in this preferred embodiment, each connection device is located along the same plane as the web22, and under the web. In other words, even if the connection devices20may not be the same thickness as the web22, these elements20and22are arranged approximately in the same plane perpendicular to the floor4.

The connection devices20shown onFIGS. 2 and 3are in the form of a tenon, preferably flat and triangular, each being provided with a through orifice32. As mentioned above and as visible onFIG. 3, the tenon20is effectively located in the same plane (not shown) as the web22, such that it forms the geometric extension of this web.

In this preferred embodiment of the present invention, the choice of a tenon to form the connection device20is made due to the fact that the connecting rod14of the associated attachment assembly10has a clevis shaped top end14b. In this way, the clevis14bis provided with two heads34a,34bwith a spacing close to the thickness of the tenon20, and in which two orifices36a,36bprovided on these heads34a,34brespectively, are in line with the through orifice32, so that the pin18can pass through them and also this orifice32. The mechanical connection between the tenon20and the clevis14bcan the be finalized by screwing a nut38onto the end of the pin18, which bears on the outside on one of the two heads34a,34b, the nut38bearing on the outside on the other of the two heads34a,34b.

FIG. 3ashows a seat rail8according to an alternative to the preferred embodiment that has just been described. This rail8inFIG. 3ais approximately identical to the rail8inFIGS. 2 and 3, and note in this respect that elements of the figures marked with the same numeric references correspond to identical or similar elements.

In this alternative, only the connection device120is different from the connection device20described above. The device120is in the form of a clevis located along the geometric prolongation of the web22and below the web, still being separated from it by the bottom flange26. In other words, the clevis120comprises a base120clocated in the same plane as the web22, starting from which two clevis heads120a,120bextend located on each side of the above mentioned plane and parallel to it.

This configuration is used when the attachment assembly10associated with the device120comprises a connecting rod115for which the top end115bis in the form of a tenon. The tenon115bis approximately the same thickness as the spacing of the heads120a,120band can be assembled on the clevis120using a pin18, this pin passing through two through orifices132a,132bprovided on heads120a,120b, respectively, and an orifice136formed in the tenon115bof the connecting rod115.

FIGS. 4 to 6diagrammatically illustrate different steps in a first preferred embodiment of the manufacturing process according to the invention, use of this first preferred embodiment making it possible to obtain a seat rail8like that shown onFIGS. 2 and 3.

With reference toFIGS. 4 and 5jointly, a first step consists firstly of making a single piece assembly50comprising the web22, the top flange24and the bottom flange26, and a plate52parallel to the web22and projecting from the outer surface26of the bottom flange26. Naturally, the plate52extends over a length identical to the length of elements22,24and26, also corresponding to the length of the final rail8, and possibly up to 10 m or more.

Note that this step is preferably done by rolling, such that finishing operations may naturally be performed on elements22,24and26obtained after this step.

Furthermore, as the connection devices20required need to be in line with the web22as shown onFIG. 3, the plate52of the assembly50is also located along the same line as web22, namely in a plane perpendicular to flanges24,26, while being separated from this web22by the bottom flange26.

This plate52is intended to form the connection devices20after machining, as shown diagrammatically onFIG. 6in which the cross-hatched parts54and56of the single piece assembly50indicate portions of the plate52to be eliminated by machining to show the connection devices20, and the associated through orifices32. Note that in this first preferred embodiment, the machining step of the plate52is done such that all removed parts54, namely parts that expose the connection devices20and not the through orifices32, extend as far as the outer surface26aof the top flange26. Thus, after this machining step, the only remaining elements of the plate52are the connection devices20projecting from the outer surface26aof the bottom flange26.

Note for information that the seat attachment means28are not shown onFIGS. 4 to 6, but they could naturally be provided on the single piece assembly15above the top flange24, without departing from the scope of the invention. Note also that the thickness e of the plate52of the single piece assembly50is preferably exactly the same as the thickness of the connection devices20, so as to facilitate and shorten the machining step. Similarly, with the same purpose of facilitating the machining operation of the plate52, the height of the plate H may be identical to the height of the connection devices20.

In the second preferred embodiment of a manufacturing method according to the invention, a single piece assembly50is firstly made in the same way as is indicated in the description of the first preferred embodiment.

Only the latter step to machine the plate52is different from the step described above, in that it is made such that at least one of the eliminated parts54, namely those that expose the connection devices20and not the through orifices32, does not extend as far as the outer surface26aof the top flange26. Thus, after this machining step, the connection devices20projecting from the outer surface26aof the bottom flange26are no longer the only remaining elements of plate52, since some of them are connected by a strip of unmachined material58extending from the same outer surface26aover a height h less than the height H of the connection devices20and the plate52. Naturally, as can be seen onFIGS. 7 and 8, the heights h and H are measured along a direction perpendicular to the flanges24,26, which themselves are parallel to the floor4when the rails8are installed on the aircraft.

Note that the fact of providing such a strip of material58connecting two directly consecutive connection devices20and being made in a single piece with the other elements of the rail8within a thickness equal to the thickness of the connection devices20, increases the longitudinal stiffness of the rail assembly8, so that it can be made to be extremely long.

Obviously, those skilled in the art could make various modifications to the seat rails8for an aircraft cabin and the methods of manufacturing seat rails that have just been described above as non-limitative examples only.