METHOD FOR MANUFACTURING AN AIRCRAFT SEAT PART

Abstract

The invention relates to a method for manufacturing a part (10) for an aircraft seat comprising: a step of positioning a heating frame (28) around a stacked structure (11), - a step of locally heating at least one edge (29.1, 29.2, 30.1, 30.2) of the stacked structure (11) using a heating frame (28), - a step of externally heating the entire stacked structure (11), - a step of positioning the stacked structure (11) inside a thermoforming mould (39) provided with cutting punches (41, 42), - a step of closing the thermoforming mould (39) and applying a vacuum to the interior of the thermoforming mould (39), so as to simultaneously perform, during the same step of shaping the first cover (13.1) and the second cover (13.2), a step of heat sealing at least one edge of the first cover (13.1) to at least one edge of the second cover (13.2), bonding the first cover (13.1) and the second cover (13.2) to the foam core (12), and cutting the stacked structure (11) along the circumference thereof using cutting punches (41, 42).

Description

[0001] DESCRIPTION

[0002] TITLE: METHOD FOR MANUFACTURING A SEAT PART

[0003] BY PLANE

[0004] The present invention relates to a method for manufacturing an aircraft seat part. The invention finds a particularly advantageous, but not exclusive, application in the manufacture of meal trays for economy-type aircraft seats.

[0005] Figure 1 shows a meal tray 1 according to the state of the art comprising a metal sheet 2 as well as two covers 3.1, 3.2 assembled with a core 4 made of foam.

[0006] Generally, the covers 3.1, 3.2 made of a thermoplastic material are shaped by a thermoforming process and then trimmed in a subsequent step. Mechanisms such as slides 5, fixings of a cup holder device 6, or locking systems are also mounted on the metal sheet 2 to hold these elements in position. A U-shaped profile 7 may extend along a longitudinal edge of the meal tray. The meal tray 1 is configured to cooperate with rods 8 of a support 9 intended to be fixed to an airplane seat back.

[0007] The assembly of the various components of the meal tray 1 (the covers 3.1, 3.2, the foam core 4, and the sheet 2 equipped with the various mechanisms) is carried out by a gluing operation. The mechanical connection between the covers 3.1, 3.2 is thus carried out by gluing along their edges which are placed in overlap with each other.

[0008] However, such a manufacturing process requires the use of numerous tools for shaping the covers as well as for assembling the whole unit. In addition, all assemblies, adjustments, and bonding are carried out by tedious and poorly repeatable manual operations. Many failures have been observed during tests or during the operating phase due to repeatability problems and the poor performance of the adhesives, the choice of which is limited due to the substrates used.

[0009] The overall finish is also poor due to the overlap between the edges of the two covers, which often results in glue burrs. In addition, the sheet metal used to ensure the correct positioning of the mechanisms increases the weight of the assembly.

[0010] The invention aims to effectively remedy the aforementioned drawbacks by proposing a method for manufacturing a part for an aircraft seat comprising:

[0011] - a step of positioning a heating frame around a stacked structure comprising a foam core, a first cover and a second cover made of a thermoplastic material arranged on either side of the foam core, a first film of hot-melt adhesive inserted between the first cover and the foam core and a second film of hot-melt adhesive inserted between the second cover and the foam core,

[0012] - a step of local heating of at least one edge of the stacked structure using a heating frame,

[0013] - an external heating step of the entire stacked structure,

[0014] - a step of placing the stacked structure inside a thermoforming mold equipped with cutting punches,

[0015] - a thermoforming step via closing the thermoforming mold and applying a vacuum inside the thermoforming mold, so as to simultaneously carry out during the same step a shaping of the first cover and the second cover, a heat sealing between at least one edge of the first cover and at least one edge of the second cover, a bonding of the first cover and the second cover on the foam core, and a cutting of the stacked structure along its circumference using the cutting punches.

[0016] The invention thus makes it possible to carry out, during the thermoforming step, an assembly of the different layers of material of the part while carrying out a cutting step. The invention therefore reduces the manufacturing time as well as the number of tools necessary to conform the part. The invention also makes it possible to reduce the weight of the assembly by eliminating the structural metal sheet. Furthermore, by replacing the manual gluing of the edges of the thermoplastic covers with the welding of these edges managed during the thermoforming step, failures induced by the operator are eliminated and the finish of the part is improved.

[0017] According to one implementation of the invention, prior to the local heating step, said method comprises a step of placing at least one functional insert intended to be mechanically linked with the stacked structure during the thermoforming step. This makes it possible to obtain, at the mold outlet, an aircraft seat part integrating at least part and preferably all of its functions.

[0018] According to one implementation of the invention, the functional insert is wedged in position on the heating frame so as to guarantee correct positioning of said functional insert relative to the stacked structure.

[0019] According to one implementation of the invention, the step of local heating of the edge of the stacked structure is started before the step of external heating of the entire stacked structure.

[0020] According to one implementation of the invention, the step of local heating of the edge of the stacked structure and the step of external heating of the entire stacked structure are started at the same time.

[0021] According to one implementation of the invention, the step of local heating of the edge of the stacked structure is started when the external heating is stabilized at a temperature plateau.

[0022] According to one implementation of the invention, the external heating step of the entire stacked structure is carried out in two isothermal stages.

[0023] According to one implementation of the invention, when a heating member of the heating frame has reached a temperature compatible with the heat sealing and cutting of the edge of the first cover and the second cover and a temperature of a central part of the stacked structure is homogeneous, the method comprises a step of stopping the external heating and the local heating using the heating frame. The heating member is configured so as to heat only the area in proximity to the areas to be welded to limit thermal inertia and energy consumption as much as possible.

[0024] According to one implementation of the invention, said method comprises a step of cooling the part obtained during the thermoforming step to stabilize the thermoforming of the covers, the bonding of the covers to the foam core, and the heat sealing of the edges of the covers together.

[0025] According to one implementation of the invention, the cooling step is carried out by mold impressions stabilized at a temperature lower than a solidification temperature of a material of the covers.

[0026] According to one implementation of the invention, the cooling step is carried out by regulating the temperature of the mold from a transformation temperature to a temperature lower than a solidification temperature of a material of the covers.

[0027] According to one implementation of the invention, the external heating of the stacked structure is carried out by a dedicated external heating cell or by using hot / cold temperature regulation of the mold cavities. In other words, the mold cavities itself can be used in the open position to heat the stacked structure.

[0028] According to one implementation of the invention, the mold impressions may be grained and / or marked so as to obtain a texture and / or markings on the external faces of the covers of the stacked structure.

[0029] The invention also relates to a part for an airplane seat obtained with the method as previously defined.

[0030] According to one embodiment of the invention, the part for an airplane seat may be chosen from a meal tray, a backrest, a seat, a headrest, or a privacy shell panel.

[0031] The present invention will be better understood and other characteristics and advantages will become apparent upon reading the detailed description which follows, comprising embodiments given for illustrative purposes with reference to the appended figures, presented as non-limiting examples, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which:

[0032] [Fig. 1] Figure 1, already described, is an exploded perspective view of an airplane seat meal tray according to the state of the art;

[0033] [Fig. 2] Figure 2 is an exploded perspective view of an aircraft seat meal tray according to the present invention;

[0034] [Fig. 3] Figure 3 is a top view of a heating frame arranged around a stacked structure of the meal tray according to the invention;

[0035] [Fig. 4] Figure 4 is a sectional view along plane AA of Figure 3 showing the integration of a heating resistor inside the heating frame;

[0036] [Fig. 5a] [Fig. 5b] [Fig. 5c] [Fig. 5d] [Fig. 5e] Figures 5a to 5e illustrate the different steps of the method of manufacturing an aircraft seat tray according to the present invention;

[0037] [Fig. 6a] [Fig. 6b] [Fig. 6c] Figures 6a to 6c show the evolution, as a function of time, of the temperature of the material, of the heating frame, of an external heating cell, and of a thermoforming mold for different possible thermal cycles for the implementation of the manufacturing method according to the invention;

[0038] [Fig. 7a] [Fig. 7b] [Fig. 7c] [Fig. 7d] Figures 7a to 7d are schematic sectional views illustrating different possible geometries of the cutting punches integrated into the thermoforming mold.

[0039] It should be noted that, in Figure 2 and the following figures, the structural and / or functional elements common to the different embodiments have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0040] Figure 2 shows an exploded perspective view of an airplane seat meal tray 10 comprising a tray consisting of a stacked structure 11 also called a "sandwich structure" formed by a stack of different layers of materials. In this case, the stacked structure 11 is formed by a foam core 12, a first cover 13.1 and a second cover 13.2 made of a thermoplastic material, and hot-melt adhesive films 14.1, 14.2 arranged between the covers 13.1, 13.2 and the foam core 12. The hot-melt adhesive films

[0041] 14.1, 14.2 are made of a glue capable of melting at high temperature.

[0042] The foam core 12 may be obtained by machining a block of foam or by expanding a polyurethane foam material inside a mold so as to be preformed to be assembled with or without a slight excess thickness to improve bonding with the covers 13.1, 13.2. The first cover 13.1 and the second cover 13.2 may be made from thermoforming plates with thicknesses between 1 and 3 mm made of polycarbonate (PC) or polyvinyl chloride (PVC).

[0043] The tablet 10 further comprises two slides 15 each intended to cooperate with a rod 16 of a tablet support 17 mounted on a seat back. The tablet support 17 is articulated so as to be able to move the tablet 10 from a stored position in which the tablet 10 is pressed against a rear face of the backrest to a deployed position in which the tablet 10 has a substantially horizontal orientation to allow the passenger to place a meal tray or objects thereon. The slides 15 and the rods 16 make it possible to ensure translational movement of the tablet 10 relative to the support 17 when the tablet 10 is in the deployed position. The positioning of the tablet 10 can thus be adapted to the morphology of the passenger. The slides 15 are associated with pads 19. Preferably, a slide 15 has a parallelepiped body so as to be able to be housed between an impression made in the foam core 12 and a cover

[0044] 13.1, 13.2 so as to limit any hollows and shape defects during thermoforming of the covers 13.1, 13.2 and to provide good support for gluing.

[0045] The shelf 10 also comprises a U-shaped profile 21 extending along a longitudinal edge. The profile 21 may be made of a metallic material, in particular aluminum, or of a plastic material, in particular polycarbonate (PC). A cup holder device 22 may also be provided, fixed to a rear face of the shelf 10 and usable when the shelf 10 is in the stored position.

[0046] The components surrounded by the solid line 24 are used in the manufacturing method according to the invention. The components surrounded by the broken line 25, namely the tablet support 17 and the cup holder device 22, are not involved in this method. However, a cup holder attachment insert 22 may be integrated during the manufacture of the stacked structure 11 forming the tray of the meal tablet 10.

[0047] The various stages of manufacturing the tablet 10 according to the invention are described below, with reference to FIGS. 5a to 5e.

[0048] As illustrated in Figure 5a, a heating frame 28, which may also be called a "moving frame", is arranged around the stacked structure 11 comprising the foam core 12, the first cover 13.1 and the second cover 13.2 arranged on either side of the foam core 12, a first film of hot-melt adhesive 14.1 arranged between the first cover 13.1 and the foam core 12, and a second film of hot-melt adhesive 14.2 arranged between the second cover 13.2 and the foam core 12. The stacked structure 11 is thus formed by stacking the following elements: cover 13.1 - adhesive film 14.1 - foam core 12 - adhesive film 14.2 - cover 13.2. The different elements located between the covers 13.1, 13.2 are sandwiched between two adjacent elements.

[0049] As can be seen in Figure 3, the movable frame 28 extends along two longitudinal edges 29.1, 29.2 and two transverse edges 30.1, 30.2 of the stacked structure 11. The movable frame 28 is provided with one or more heating members 32, such as one or more electrical resistors. The heating member(s) 32 are configured to provide local heating of the edges of the stacked structure 11, in particular the longitudinal edge 29.1 and the two transverse edges 30.1, 30.2. The heating member(s) 32 are configured so as to heat only the area in proximity to the areas to be welded to limit thermal inertia and energy consumption as much as possible. In other applications, the heating frame 28 may be configured to heat a different number of edges of the stacked structure 11.Advantageously, the heating frame 28 comprises a vacuum maintenance system making it possible to guarantee the application of vacuum inside the mold 39 during the thermoforming step.

[0050] This is particularly well suited to a tablet 10 comprising a profile 21 made of metal positioned along the longitudinal side, since it is not necessary to heat this side to ensure the welding between the edges of the two covers 13.1, 13.2. Such local heating of the edges of the stacked structure 11 makes it possible to obtain a high temperature at the edge of the covers 13.1, 13.2 in order to allow the welding of the covers 13.1, 13.2 when they are brought into contact and to facilitate the subsequent cutting of the covers 13.1, 13.2 without degrading the material and the surface condition of the part. Alternatively, in the case where the profile 21 is made of a thermoplastic material, the heating frame 28 ensures heating of the 4 edges 29.1, 29.2, 30.1, 30.2 of the stacked structure 11.

[0051] As illustrated in Figure 4, a heating member 32 is disposed inside a groove 33 of the heating frame 28. The heating member 32 may have a pointed shape so as to precisely heat a corresponding edge 29.1, 29.2, 30.1, 30.2 of the stacked structure 11 along which the heating member 32 extends.

[0052] The heating frame 28 may also ensure indexing in position of one or more functional inserts relative to the stacked structure 11 so as to guarantee correct positioning of the insert(s) inside the part at the end of the process. Thus, a rod 16 may be wedged in position on the heating frame 28 via a shape 35 visible in FIG. 3, such as a housing provided in the heating frame 28 intended to receive one end of the rod 16. The slides 15 fixed on the rods 16 may be positioned on shapes machined in the foam core 12.

[0053] The term "functional insert" means any added element intended to be mechanically linked to the stacked structure 11 to provide a particular function (fixing, reinforcement, articulation, sliding, locking, or other). The functional inserts take the form of rods and sliding rails for the manufacture of a meal tray 10 but they could take the form of other elements for the manufacture of another seat element, as explained in more detail below.

[0054] The frame 28 is configured to ensure that the various elements of the stacked structure 11 are held in place during the handling phases and to allow the application of vacuum inside the mold 39 during the thermoforming phase.

[0055] Figure 5b shows an external heating cell 36 used to carry out an external heating step of the entire stacked structure 11. For this purpose, the heating cell 36 comprises two heating walls 37 intended to be positioned on either side of the stacked structure 11. The heating cell 36 advantageously provides radiation heating of the entire stacked structure 11 via ceramic walls. The external heating cell 36 can be mobile or fixed.

[0056] As can be seen in Figure 5c, the heating frame 28 and the stacked structure 11 are placed inside a thermoforming mold 39. The thermoforming mold 39 is equipped with cutting punches 41, 42 visible in Figure 4. The cutting punches 41, 42 extend along at least one edge of the covers 13.1, 13.2. The cutting punch 41 is integral with an upper imprint of the mold 39 and the cutting punch 42 is integral with a lower imprint of the mold 39.

[0057] The geometry of the cutting punches 41, 42 can be adapted according to the materials used, the thermal cycle applied, and the geometry of the desired final product.

[0058] Thus, as illustrated by figure 7a, a height H and a thickness E of the punches 41, 42 may vary from one application to another.

[0059] As illustrated in Figure 7b, the contact area between the punches 41, 42 may be flat, sharp for pointed punches, or of complex shape with a step relative to the main contact area.

[0060] As illustrated in Figure 7c, an opening angle A1, A2 of the punches 41, 42 may also vary depending on the application. As illustrated in Figure 7d, the contact kinematics of the punches 41, 42 may be flat contact according to the arrows F1 and F2 or shear contact according to the arrows F3 and F4.

[0061] It should be noted that in an alternative implementation of the method, the external heating of the stacked structure 11 could be carried out using hot / cold temperature regulation of the mold cavities 39. In other words, the mold cavities 39 itself could be used in a slightly open position to heat the stacked structure 11.

[0062] As illustrated in Figure 5d, the method comprises a thermoforming step carried out by closing the mold 39 and applying a vacuum inside the mold 39. The thermoforming is a "double-sided" thermoforming carried out by the impressions of the mold 39 on the two covers 13.1, 13.2 each located at one end of the stacked structure 11. Then, during the same step, a shaping of the first cover 13.1 and the second cover 13.2, a heat-sealing between the edges of the first cover 13.1 and the edges of the second cover 13.2, a cutting of the stacked structure 11 along its circumference using the cutting punches 41, 42, a gluing of the first cover 13.1 and the second cover 13.2 onto the foam core 12, as well as a mechanical connection of the slides 15 with the stacked structure. 11.

[0063] Thus, the materials of the two covers 13.1, 13.2 are welded at the edges under the action of heat to form a weld bead 44 along their edges (see figure 4). The weld bead 44 has a mechanical strength adapted to the lifetime requirements of the product. The geometry of the weld bead 44 formed between the two covers 13.1, 13.2 depends on the shape of the cutting punches 41, 42 as well as the closing speed parameter of the thermoforming mold 39.

[0064] The foam core 12 may have a slight excess thickness, so that closing the mold 39 slightly crushes the foam core 12 to improve the bonding of the covers 13.1, 13.2 to the foam core 12 via the glue films 14.1, 14.2. The method also includes a step of cooling the part obtained during the thermoforming step to stabilize the thermoforming of the covers 13.1,

[0065] 13.2, the bonding of the covers 13.1, 13.2 to the foam core 12, and the heat-sealing of the edges of the covers 13.1, 13.2 together. This cooling step may be carried out either by imprints of the mold 39 stabilized at a temperature lower than the solidification temperature of a material of the covers 13.1, 13.2, or by a temperature regulation of the mold 39 from a transformation temperature to a temperature lower than a solidification temperature of a material of the covers 13.1, 13.2. For this purpose, the mold 39 may include a liquid cooling network integrated into the imprints.

[0066] After opening the thermoforming mold 39 shown in Figure 5e and removing the heating frame 28, the meal tray 10 is in its final finished state with all its functions integrated.

[0067] The impressions of the mold 39 may be grained and / or marked so as to obtain a texture and / or markings on the external faces of the covers 13.1,

[0068] 13.2.

[0069] Various possible thermal cycles for implementing the manufacturing method according to the invention are described below with reference to Figures 6a to 6c. The temperatures indicated may vary depending on the material used for the various components. The temperature values ​​indicated below are particularly well suited for covers 13.1, 13.2 made of polycarbonate (PC), a foam core made of a Polyethersulfone (PES) material as well as polyester-based adhesive films 14.1, 14.2.

[0070] In these figures, curve C1 corresponds to the temperature of the material of the stacked structure 11. Curve C2 corresponds to the temperature of the heating frame 28. Curve C3 corresponds to the temperature of the heating cell 36. Curve C4 corresponds to the temperature of the thermoforming mold 39. Curve C5 corresponds to the state of the thermoforming mold 39. When curve C5 is in state 0, the mold 39 is open while when the curve is in state 1, the mold 39 is closed and the vacuum is applied inside the mold 39. In the implementation of figure 6a, the step of local heating of the edges of the stacked structure 11 (cf. curve C2) is started before the step of external heating of the entire stacked structure 11 (cf. curve C3).

[0071] Thus, between times t0 and t1, the heating frame 28 ensures local heating of the edges of the stacked structure 11. The temperature of the mold 39 remains constant at a temperature Tm between 70 and 120°C.

[0072] From time t1, the external heating of the stacked structure 11 begins (see curve C3). The external heating temperature as well as the temperature of the heating frame 28 are maintained at an isothermal level P1 between 130 and 170°C between times t1 and t2.

[0073] Between times t2 and t3, the temperature of the heating frame 28 (see curve C2) is kept constant at the isothermal level between 130°C and 170°C, while the temperature of the external heating cell 36 increases to a second isothermal level P2 between 180°C and 230°C (see curve C3).

[0074] Between times t3 and t4, the temperature of the external heating cell 36 is kept constant at the second isothermal stage P2 to guarantee optimal thermoforming of the covers 13.1, 13.2.

[0075] At time t4, when the heating frame 28 has reached a temperature compatible with the heat sealing and cutting of the edges of the first cover 13.1 and the second cover 13.2 and a temperature of a central part of the stacked structure 11 is homogeneous, the heating of the heating frame 28 is cut off (see curve C2) as well as the external heating of the heating cell 36 (see curve C3). The mold 39 is then closed and a vacuum is applied inside the mold 39 during the thermoforming step (see curve C5). This step during which the covers 13.1, 13.2 are shaped, the edges of the covers 13.1, 13.2 are heat sealed, the stacked structure 11 is trimmed and the functional inserts of the tablet 10 are integrated lasts until time t5. Furthermore, between times t4 and t5, the mold 39 cools the tablet 10 to a demolding temperature.The cooling of the part is thus carried out in the mold 39 having a temperature lower than a solidification temperature of a material of the covers 13.1, 13.2. The temperature as well as the cooling rate can be adapted according to the materials used. At time t5, the mold 39 is opened and the suction is cut off. The part can then be removed from the mold 39.

[0076] The duration T1 of preheating the edges by the heating frame 28 may be between 5 and 15 minutes. The duration T2 of cycle time may also be between 10 and 15 minutes. The duration T3 of closing the mold 39 and applying the vacuum is between 2 and 5 minutes.

[0077] In the implementation of Figure 6b, the step of local heating of the edges of the stacked structure 11 (see curve C2) and the step of external heating of the entire stacked structure 11 (see curve C3) are started at the same time.

[0078] Thus, between times t0 and t1, the heating frame 28 and the heating cell 36 are activated until the material reaches an isothermal plateau P1 between 130 and 170°C. The temperature Tm of the mold 39 remains constant at a temperature between 70 and 120°C.

[0079] Between times t1 and t2, the temperature of the heating frame 28 is kept constant at the isothermal level P1 (see curve C2), while the temperature of the heating cell 36 (see curve C3) increases to a second isothermal level P2 between 180°C and 230°C.

[0080] Between times t2 and t3, the temperature of the external heating cell 36 (see curve C3) is kept constant at the second isothermal stage P2 to guarantee optimal thermoforming of the covers 13.1, 13.2.

[0081] At time t3, when the heating member(s) 32 have reached a temperature compatible with the heat sealing and cutting of the edges of the first cover 13.1 and the second cover 13.2 and a temperature of a central part of the stacked structure 11 is homogeneous, the heating of the heating frame 28 is cut off (see curve C2) as well as the external heating of the heating cell 36 (see curve C3). The mold 39 is then closed and a vacuum is applied inside the mold 39 during the thermoforming step (see curve C5). The thermoforming step lasts until time t4. Furthermore, between times t3 and t4, the mold 39 cools the tablet 10 to the demolding temperature. At time t4, the mold 39 is opened and the suction is cut off. The part can then be removed from the mold 39.

[0082] The cycle time T1' may also be between 5 and 15 minutes. The duration T2' of closing the mold 39 and applying the vacuum is between 2 and 5 minutes.

[0083] In the implementation of figure 6c, the local heating step of the edges of the stacked structure 11 (see curve C2) is started when the external heating is stabilized at the temperature level P2 (see curve C3).

[0084] More precisely, between times t0 and t1, the external heating cell 36 (see curve C3) is activated until the material reaches a first isothermal plateau P1 between 130 and 170°C (see curve C1). The temperature of the mold 39 remains constant at a temperature Tm between 70 and 120°C.

[0085] Between times t1 and t2, the temperature of the external heating cell 36 (see curve C3) increases to a second isothermal level P2 between 180°C and 230°C.

[0086] Between times t2 and t3, the temperature of the external heating cell 36 is kept constant at the second isothermal stage P2 while the heating frame 28 is activated (see curve C2) in order to obtain a high temperature of the material guaranteeing optimal thermoforming of the covers 13.1, 13.2.

[0087] At time t3, when the heating member(s) 32 have reached a temperature compatible with the heat sealing and cutting of the edges of the first cover 13.1 and the second cover 13.2 and a temperature of a central part of the stacked structure 11 is homogeneous, the heating of the heating frame 28 is cut off (see curve C2) as well as the external heating of the heating cell 36 (see curve C3). The mold 39 is then closed and a vacuum is applied inside the mold 39 during the thermoforming step (see curve C5). The thermoforming step lasts until time t4. Furthermore, between times t3 and t4, the mold 39 cools the tablet 10 to a demolding temperature. At time t4, the mold 39 is opened and the suction is cut off. The part can then be removed from the mold 39.

[0088] The cycle time duration T1' may also be between 10 and 15 minutes. The duration T2' of closing the mold 39 and applying the vacuum T3 is between 2 and 5 minutes.

[0089] It should be noted that in all cases, the external heating step of the entire stacked structure 11 (see curve C3) is carried out according to the two isothermal stages P1 and P2. This ensures progressive heating of the material, preventing its deterioration.

[0090] Alternatively, the external heating is carried out directly in the mold 39 in the open state as explained previously.

[0091] The method has been described for the production of a meal tray 10 but this method could also be implemented with any other aircraft seat part having a so-called "sandwich" structure in which several layers of different materials are stacked, such as for example a seat, a backrest, or a headrest, or a privacy shell panel. Some parts may integrate various functional inserts 15, such as a fixing rod for a headrest, a reinforcement or a joint for a backrest or a seat. Other parts, in particular the privacy shell panel, may be devoid of a functional insert 15. The step of indexing a functional insert 15 relative to the heating frame 28 is therefore an optional step of the method.

[0092] Of course, the various features, variations and / or embodiments of the present invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

[0093] 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 may be envisaged by those skilled in the art within the scope of the present invention and in particular all combinations of the different modes of operation described above, which may be taken separately or in combination.

Claims

DEMANDS 1. A method for manufacturing a part (10) for an aircraft seat characterized in that it comprises: - a step of positioning a heating frame (28) around a stacked structure (11) comprising a foam core (12), a first cover (13.1) and a second cover (13.2) made of a thermoplastic material arranged on either side of the foam core (12), a first film of hot melt adhesive (14.1) interposed between the first cover (13.1) and the foam core (12) and a second film of hot melt adhesive (14.2) interposed between the second cover (13.2) and the foam core (12), - a local heating step of at least one edge (29.1, 29.2, 30.1, 30.2) of the stacked structure (11) using a heating frame (28), - an external heating stage of the entire stacked structure (11), - a step of placing the stacked structure (11) inside a thermoforming mold (39) equipped with cutting punches (41, 42), - a thermoforming step via a closing of the thermoforming mold (39) and a vacuum application inside the thermoforming mold (39), so as to carry out simultaneously during the same step a shaping of the first hood (13.1) and the second hood (13.2), a heat sealing between at least one edge of the first hood (13.1) and at least one edge of the second hood (13.2), a bonding of the first hood (13.1) and the second hood (13.2) onto the foam core (12), and a cutting of the stacked structure (11) along its circumference using the cutting punches (41, 42).

2. A method according to claim 1, characterized in that prior to the local heating step, said method comprises a step of setting up at least one functional insert (15) intended to be mechanically linked with the stacked structure (11) during the thermoforming step.

3. A method according to claim 2, characterized in that the functional insert (15) is secured in position on the heating frame (28) so as to guarantee a correct positioning of said functional insert (15) in relation to the stacked structure (11).

4. Method according to claim 1 or 2, characterized in that the local heating step of the edge (29.1, 29.2, 30.1, 30.2) of the stacked structure (11) is started before the external heating step of the entire stacked structure (11).

5. Method according to claim 1 or 2, characterized in that the local heating step of the edge (29.1, 29.2, 30.1, 30.2) of the stacked structure (11) and the external heating step of the entire stacked structure (11) are started at the same time.

6. Method according to claim 1 or 2, characterized in that the local heating step of the edge (29.1, 29.2, 30.1, 30.2) of the stacked structure (11) is started when the external heating is stabilized at a temperature plateau (P2).

7. A method according to any one of claims 1 to 5, characterized in that the external heating step of the entire stacked structure (11) is carried out in two isothermal stages (P1, P2).

8. A method according to any one of claims 1 to 6, characterized in that when a heating element (32) of the heating frame (28) has reached a temperature compatible with heat sealing and cutting an edge of the first hood (13.1) and the second hood (13.2) and a temperature of a central part of the stacked structure (11) is homogeneous, the method includes a step of stopping the external heating and the local heating using the heating frame (28).

9. A method according to any one of claims 1 to 7, characterized in that it comprises a cooling step of the part (10) obtained during the thermoforming step to stabilize the thermoforming of the hoods (13.1, 13.2), the bonding of the hoods (13.1, 13.2) onto the foam core (12), and the heat sealing of the edges of the hoods (13.1, 13.2) together.

10. Method according to claim 9, characterized in that the cooling step is carried out by mold cavities (39) stabilized at a temperature lower than a solidification temperature of a material of the hoods (13.1, 13.2).

11. Method according to claim 9, characterized in that the cooling step is carried out by temperature regulation of the mold (39) from a transformation temperature to a temperature lower than a solidification temperature of a material of the hoods (13.1, 13.2).

12. A method according to any one of claims 1 to 11, characterized in that the external heating step is carried out by a dedicated external heating cell (36) or by cavities of the mold (39) in the open state.

13. Part for an aircraft seat obtained by the process as defined according to any one of the preceding claims.

14. Part for an aircraft seat according to claim 13, characterized in that it is selected from a meal tray (10), a backrest, a seat, a headrest, or a privacy shell panel.