Seat unit provided with a tubular seat-base structure

A seat unit, in particular for an aircraft cabin, includes a seat provided with seat cushion and backrest kinematics, and a seat-base structure on which the seat is mounted. The seat-base structure includes a frame with a tubular structure including a first lower tube and a second lower tube, the first lower tube and the second lower tube each carrying at least one bolt intended to be fastened to rails, and two fastening feet for fastening the seat cushion and backrest kinematics. A fastening foot is formed by a tube connected by one of its ends to the first lower tube of the frame and by its other end to the second lower tube of the frame.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase application of International Patent Application PCT/EP2021/068885 (“the '885 application”), filed on Jul. 7, 2021 and titled “SEAT UNIT PROVIDED WITH A TUBULAR SEAT-BASE STRUCTURE,” which application is related to and claims priority benefits of France Patent Application No. 2007447 (“the '447 application”), filed on Jul. 16, 2020. The '885 and '447 applications are hereby incorporated in their entireties by this reference.

The present invention relates to a seat unit provided with a lower tubular-type seat structure. The invention finds a particularly advantageous, but not exclusive, application with aircraft seat units of the “business class” type. By “seat unit” it is meant the seat as such, as well as all the elements associated with the seat, such as a privacy shell, the lower seat structure and, where applicable, an armrest, a console, or other.

A lower seat unit structure is an interface part providing a mechanical connection between the rails of the aircraft and at least one element of the seat, such as a seating part and backrest kinematics.

As shown inFIG.1, a lower seat structure1described in document EP18159172 comprises, in a manner known per se, a reinforcement panel2as well as a front cross member3and a rear cross member4located on either side other of the reinforcement panel2. The cross members3and4generally consist of beams.

The mounting of this assembly is carried out by means of two spars5,6each provided with a groove receiving an edge of the reinforcement panel2. The beams5,6are fixed to the panel2for example by means of rivets and the mounting of the spars5,6on the beams3,4is carried by means of screws.

The lower structure1further comprises legs7on its upper face for the fixation to a seating part and backrest kinematics as well as brackets8allowing the fixation of a privacy shell.

The lower structure1is also provided with locks9carried by the cross members3,4. The locks9ensure the mechanical connection between the lower seat structure1and the rails extending along the floor of the aircraft cabin. The mountings of the spars, the fasteners of the rails and the shells on the beams are made by means of screws.

Alternatively, as shown inFIG.2, the lower seat structure1described in document FR1912243 comprises a machined plinth11provided on the underside with locks9providing a mechanical connection between the lower structure1and the rails of the aircraft cabin. The lower structure1further comprises legs7on its upper face for the fixing to a seating part and backrest kinematics as well as brackets8allowing the fixing of the privacy shell.

The lower seat structures can have multiple possible configurations linked in particular to the adaptation of the angle of the seats with respect to the axis of the cabin, to the particular platform of the aircraft, as well as to the specific requests of the airlines. This involves a wide variety of interface parts for mounting locks as well as fixing brackets.

This multiplication of interface parts generates a complex design, additional mass, as well as risks of mounting errors and significant mounting time.

Also, since tolerances are dependent on dimension figures for mechanical mountings, the tolerance of the mechanical mounting increases with the number of interface parts.

The mounting of a large number of parts also limits the space available for fixing electrical boxes to supplying, through a set of electrical harnesses, the various electrical components of the seat unit, such as seat actuators or video screens of an IFE-type entertainment system ((IFE=Inflight Entertainment).

Furthermore, in the context of compliance with new increasingly restrictive regulations, known lower structures are beginning to reach their limits in terms of resistance to mechanical forces in the event of impact.

The invention aims to effectively remedy the aforementioned drawbacks by proposing a seat unit, in particular for an aircraft cabin, comprising:a seat provided with a seating part and backrest kinematics, anda lower seat structure on which the seat is mounted,said lower seat structure comprising a tubular-structure frame comprising:a first lower tube and a second lower tube, the first lower tube and the second lower tube each carrying at least one lock to be fixed on rails, andtwo fixing legs for the seating part and backrest kinematics, a fixing leg being formed by a tube connected by one of its ends to the first lower tube of the frame and by its other end to the second lower tube of the frame.

The invention thus makes it possible, thanks to the tubular structure of the lower structure, to give the lower structure greater flexibility of design and greater modularity by allowing movement of the fasteners according to a position of the rails in the aircraft cabin without creating new interface parts.

The tubular design of the assembly also makes it possible to control the zone undergoing torsion in the event of a crash, which improves the behavior of the structure undergoing strong mechanical stress. Indeed, while maintaining good rigidity in the directions related to the crash, the tubular structure creates a flexibility allowing deformation of the structure according to that of the floor of the aircraft cabin.

The tubular structure, which can be made on a welding template, also makes it possible to better manage tolerances by eliminating the dispersion of play generated by screw mountings. The invention also allows mass savings compared to the known lower seat structures. The invention also makes it possible to clear a space under the seat, which facilitates the integration of the electrical boxes.

Furthermore, the invention makes it easier to dismount the frame during maintenance operations to access a defective electrical box located under the seat. It should also be noted that by integrating the fixing legs into the lower seat structure, the invention facilitates the installation of the seating part and backrest kinematics on the frame.

According to one embodiment of the invention, the fixing legs project with respect to a plane in which the first lower tube and the second lower tube of the frame extend.

According to one embodiment of the invention, a fixing guide is arranged on an upper portion of a corresponding fixing leg.

According to one embodiment of the invention, the first lower tube and the second lower tube are bent so that a gap between the first lower tube and the second lower tube is variable when moving from one end of the tubes to the other.

According to one embodiment, said seat unit further comprises a privacy shell.

According to one embodiment of the invention, the lower seat structure further comprises a reinforcing belt formed by a plurality of tubes, at least part of the privacy shell being fixed to said reinforcing belt.

According to one embodiment of the invention, the reinforcement belt is surrounded by a part of the privacy shell.

According to one embodiment of the invention, the reinforcement belt extends vertically over a height between 12 cm and 50 cm, and preferably of about 38 cm.

According to one embodiment of the invention, the privacy shell comprises a lower part and an upper part, so that it is possible to dismount only the lower part to access electrical boxes under the seat.

According to one embodiment of the invention, at least one passage trough for electrical harnesses is fixed to the reinforcement belt.

According to one embodiment of the invention, said seat unit comprises three locks so as to have a three-fixation-points configuration.

According to one embodiment of the invention, a lock is associated with a lock support.

According to one embodiment of the invention, the lock support comprises a single opening for the passage of a lower tube so as to allow movement of the lock support along the lower tube before immobilization by welding said lock support in a position corresponding to a positioning of a rail.

According to one embodiment of the invention, the lock support comprises two openings for the passage of the first lower tube and of the second lower tube respectively so as to allow movement of the lock support along the lower tubes before immobilization by welding said lock support in a position corresponding to a positioning of a rail.

According to one embodiment of the invention, the lock support is made of two parts.

The invention further relates to an airplane comprising a plurality of seat units as previously defined.

It should be noted that, inFIG.3aand following, the structural and/or functional elements common to the various embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

FIGS.3aand3bshow a seat unit20, in particular for an airplane cabin, comprising a seat21, a privacy shell22which extends around the seat21so as to isolate the passenger from the external environment, a console23, an armrest24, as well as a lower seat structure25for fixing the assembly to the rails26of the aircraft cabin.

More specifically, the seat21comprises a seating part28as well as a reclining backrest31. The seat21is preferably a “business” type seat movable between a seat position and a bed position in which the various components of the seat21extend along a substantially horizontal plane. A seating part and backrest kinematics29visible inFIGS.4aand4bcomprises mechanical components making it possible to ensure movement of the seating part28and the backrest31, in particular to pass from the seat position to the bed position, and vice versa.

The console23has an upper face32on which the passenger can place objects, as shown inFIGS.3aand3b. The console23may incorporate a removable meal flap33, storing equipments34, as well as electrical outlets35for recharging electronic devices. The console23may also include an internal foot housing36, clearly visible inFIG.8b, for receiving the feet of a rear passenger when the seat21of said rear passenger is in the bed position.

The seating part and backrest kinematics29, the privacy shell22, and the console23are mounted on the lower seat structure25, which is fixed to the rails26of the aircraft cabin by means of locks38.

As can be seen inFIGS.3aand6, electrical boxes39are positioned under the seat21. These electrical boxes39are provided for supplying, though a set of electrical harnesses40, the various electrical components of the seat unit20, such as seat actuators21or video screens of an IFE-type entertainment system (IFE=Inflight Entertainment).

Advantageously, as can be seen inFIGS.5and6, the lower seat structure25comprises a frame41with a tubular structure. By “frame with a tubular structure” it is meant a frame41formed by a plurality of hollow tubes. Preferably, the tubular structure is a “mechanically welded” type structure, that is to say a structure formed by hollow metal tubes welded together. Advantageously, the metal tubes are made of steel. Alternatively, the tubes could however be made of another metallic material, such as aluminum or magnesium, or any other material suitable for the application. The tubes preferably have a round or oval section which is particularly well suited to withstand torsional forces associated with the deformation of the floor of the aircraft cabin during a crash. Alternatively, the tubes could however have a rectangular, square, trapezoidal, triangular section or any other shape suitable for the application.

The section may be constant over the length of the tubes or variable so as to locally reinforce the structure in areas subjected to particularly high mechanical stresses via welded or butted reinforcements or via deformation of the tube by a butted tubing process. Indeed, the tubular structure makes it possible to independently define the thickness of material with respect to the internal diameter of a tube in order to adapt the rigidity of the lower structure.

In this case, the frame41comprises a first lower tube43and a second lower tube44. The first lower tube43and the second lower tube44each carry at least one lock38to be fixed on the rails26of the aircraft cabin.

The frame41further comprises two fixing legs45of the seating part and backrest kinematics29. A fixing leg45is formed by a tube connected by one of its ends to the first lower tube43of the frame41and by its other end to the second lower tube44of the frame41.

As can clearly be seen inFIGS.4aand4b, the fixing legs45project with respect to a plane P in which the first lower tube43and the second lower tube44of the frame41extend. A fixing leg45comprises an upper portion48and two connecting portions49. One connecting portion49mechanically connects one end of the upper portion48to one corresponding lower tube43,44.

The seating part and backrest kinematics29are intended to be fixed on fixing guides51. A fixing guide51is arranged on an upper portion48of a corresponding fixing leg45so as to be easily accessible for the operator. The fixing guides51also have an indexing function in order to facilitate the positioning of the seating part and backrest kinematics29during the mounting of the seat21.

The first lower tube43and the second lower tube44are bent so that a gap between the first lower tube43and the second lower tube44is variable when moving from one end of the tubes43,44to the other, as shown inFIGS.5and6. In this case, the gap between the two lower tubes43,44tends to decrease when moving from one end on the side of the fixing legs45towards the opposite end. Such a configuration makes it possible to optimize the floor space of the lower seat structure25.

The lower seat structure25further comprises a reinforcement belt52formed by a plurality of tubes53,54. The plurality of tubes53,54of the reinforcement belt52is mechanically connected to the lower tubes43,44. The reinforcement belt52is surrounded by a portion of the privacy shell22. At least a portion of the privacy shell22is fixed to the reinforcement belt52.

The reinforcement belt52makes it possible to effectively take up the forces applied to the privacy shell22in the event of an impact. This improves the mechanical strength of the privacy shell22during a crash. In addition, due to a separate fixation of the shell22and the seat21to the lower seat structure25, such a configuration makes it possible to distribute and divide the paths of forces applied to the seat unit20during a crash.

More specifically, in the example shown, the reinforcement belt52comprises upright tubes53and a connecting tube54connecting the upright tubes53to each other. For this purpose, the upright tubes53are connected by one end to one of the lower tubes43,44and by another end to the connecting tube54. The connecting tube54extends in a substantially horizontal plane. Additional reinforcing tubes may be used to connect two adjacent upright tubes53together. Another configuration of the tubes53,54is of course possible.

Advantageously, the reinforcement belt52extends vertically over a height comprised between 12 cm and 50 cm, and preferably of about 38 cm. By “about” it is meant a variation of plus or minus 10% around the target value.

As illustrated byFIGS.8aand8b, the privacy shell22is preferably made of two parts. Thus, the privacy shell22comprises a lower part22.1and an upper part22.2, so that it is possible to dismount only the lower part22.1to access the electrical boxes39under the seat21.

As can be seen inFIGS.9and10, the fixation of the privacy shell22on the reinforcement belt52can be carried out by means of sleeves55fixed to the connecting tube54. A fixing member, such as a screw, is inserted inside a sleeve55so as to cooperate with a thread in an interface part of the shell22. Alternatively, the screws may be replaced with rivets, studs, or any other fastener suitable for the application.

The reinforcement belt52may be extended by a tubular portion56to which the console23is fixed. In this case the tubular portion56has a triangular shape corresponding to the shape of the console23.

Preferably, at least one passage trough57for electrical harnesses40is fixed to the reinforcing belt52, as shown inFIGS.6and7. To this end, the passage trough57preferably comprises removable fixation means58allowing the operator to easily fix the passage trough57on the tubes53,54of the reinforcement belt52. The removable fixation means58may for example consist of elastically deformable snap-fastening devices, for example C-shaped ones.

The electrical harnesses40from the electrical boxes39and to be connected to the various electrical components of the seat21can thus be arranged inside the passage trough57in order to facilitate their installation in the lower part of the seat21.

The seat unit20preferably includes three locks38so as to have a three-fixation-points configuration. Alternatively, the seat unit20could however have more than three locks38.

As can be seen inFIGS.11a,11b,12a,12b,13a, and13b, a lock38is associated with a lock support59. The lock38is mounted so as to rotate about a horizontal axis relative to the lock support59to facilitate, due to a degree of freedom in rotation, its positioning on a corresponding rail26. In this case, the pivoting axis of the lock38extends in a longitudinal direction with respect to the longitudinal axis of the aircraft.

The lock support59may comprise a single opening60for the passage of a lower tube43,44so as to allow movement of the lock support59along the lower tube43,44before immobilization by welding said lock support59in a position corresponding to a positioning of a rail26.

Alternatively, the lock support59on the right inFIG.5comprises two openings60,60′ for the passage of the first lower tube43and the second lower tube44respectively so as to allow movement of the lock support59along the lower tubes43,44before immobilization by welding said lock support59in a position corresponding to a positioning of a rail26. In this case, the pivoting axis of the lock38extends in a direction transversal to the longitudinal axis of the aircraft.

In the embodiment inFIGS.12aand12b, the lock support59is made of two parts.

In the embodiment ofFIGS.13aand13b, the lock support59is fixed to a corresponding lower tube43,44by means of a pin61through a corresponding lower tube43,44.

A template63shown inFIG.14is used to carry out the lower seat structure25according to the invention. The different tubes43,44,53,54of the frame41and the reinforcement belt52are maintained in position with the help of clamps64carried by columns65of the template63. The lock supports38are moved along lower tubes43,44so as to cooperate with the corresponding rails26at locations corresponding to a particular cabin configuration. A plate66makes it possible to define the gap between the fixing legs45of the seat21.

Once all the elements of the lower seat structure25are in a desired position, an operator or a robot can ensure the welding of the tubes43,44,53,54one to another as well as the welding of the lock supports38on the lower tubes43,44. The lower seat structure25is thus obtained. The template63thus allows a great modularity of the lower seat structure25which is thus easily adaptable to the configuration of the aircraft cabin, the seat21, the console23, and the positioning of the rails26.

When mounting the seat unit20inside the aircraft cabin, the lower seat structure25associated with the privacy shell22and the console23is first mounted on the rails26via lock38, as shown inFIGS.3aand4a.

Then, as shown inFIGS.3band4b, the seating part and backrest kinematics29is put in place on the fixing guides51which ensure the position indexing of the seating part and backrest kinematics29. Once the seating part and backrest kinematics29are in a correct position with respect to the privacy shell22, the seating part and backrest kinematics29are fixed to the fixing guides51with the help of suitable fixation means, such as screws or rivets.

In the example shown, the seat21has an axis forming a non-zero angle with respect to a longitudinal axis of the aircraft. Alternatively, the axis of the seat21may extend parallel to the longitudinal axis of the aircraft.

Alternatively, the seat21may have several places. Alternatively, several seats21can be installed on the same lower seat structure25.

The invention also relates to an airplane comprising a plurality of seat units20as previously defined.

Of course, the different features, variants and/or embodiments of the present invention can be associated with each other in various combinations insofar as they are not incompatible with one another or exclusive of each other. Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that a person skilled in the art may envisage in the context of the present invention and in particular any combination of the various operating modes of operation described previously, which may be taken separately or in combination.