FR3096342A1 - SEAT CUSHION EQUIPPED WITH AT LEAST ONE RIGIDIFICATION INSERT - Google Patents

Abstract

The invention relates mainly to a seat cushion (12) for a vehicle seat, in particular an airplane seat, comprising: - at least one bottom layer of foam (15) having a function of stiffening said seat cushion ( 12), - at least one upper foam layer (16.1, 16.2) having a seating comfort function, and - at least one insert (17) arranged inside the lower foam layer (15), - the insert (17) being made of a metallic material and having a hollow tubular shape of rectangular or square cross-section. Figure 1d

Description

Description Title of the invention: SEAT CUSHION PROVIDED WITH AT LEAST ONE STIFFENING INSERT

[0001] The present invention relates to a cushion (the seat provided with at least one stiffening insert.

The invention finds a particularly advantageous application with airplane seats.

[0002] In a manner known per se, cushions (the seat may include stiffening inserts placed inside a layer of foam.

These inserts can be made of a composite material or of a metallic material.

The document 1352009/0055023 thus describes inserts dc round section or in the shape of omega inserted in a layer of plastic material.

[0003] However, stress simulations have shown that the existing insert configurations do not support the cyclic shock tests representative of a passenger falling on the seat.

This implies that there is a risk of the inserts breaking or bending after a few years of use, so seat replacement should be done sooner than expected.

The invention aims to effectively remedy this drawback by proposing a seat cushion for a dc vehicle seat, in particular an airplane seat, comprising: - at least one lower dc foam layer having a function of stiffening said cushion seat, - at least one upper foam layer having a seating comfort function, and - at least one insert placed inside the lower foam layer, - the insert being made of a metallic material and having a hollow tubular shape with a rectangular or square cross-section.

The invention thus makes it possible, thanks to the configuration of the metal insert of rectangular section, to successfully pass the wear tests with impact.

The invention therefore reduces the risk of early replacement of the seat due to deformation of the inserts.

[0006] According to one embodiment, the insert is made of aluminum.

[0007] According to one embodiment, the insert has a rectangular section with straight corners.

According to one embodiment, the insert has a rectangular section with rounded corners.

According to one embodiment, a ratio between a thickness of the insert divided by a height of the insert is between 0.10 and 0.19, and is preferably around 0.15.

[0010]According to one embodiment, the lower layer of foam and the upper layer of foam are assembled together by gluing.

According to one embodiment, said seat cushion comprises a plurality of inserts, 2 including four inserts, arranged parallel to each other.

[0012]According to one embodiment, the lower layer of foam and the upper layer of foam are made of a plastic material.

[0013] According to one embodiment, the bottom foam layer is made of polyester.

According to one embodiment, the upper foam layer is made of polyurethane.

[0015] According to one embodiment, the insert has a section with dimensions of the order of 10mm×20mm and a thickness of the order of 1.5mm.

[0016] According to one embodiment, the insert has a cross-section identical to that of a luggage stop bar of an airplane seat.

[0017] The invention also relates to an aircraft seat comprising a seat cushion as previously defined.

[0018] The invention further relates to an airplane comprising a seat as previously defined.

Of course, the different characteristics, variants and/or embodiments of the present invention can be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other.

The present invention will be better understood and other characteristics and advantages will become apparent on reading the following detailed description comprising embodiments given by way of illustration with reference to the appended figures, presented by way of examples not limitations, which may be used to complete the understanding of the present invention and the description of its realization and, where appropriate, contribute to its definition, on which:

Figure la is a perspective view of an aircraft seat according to the invention comprising a seat cushion provided with inserts seen by transparency;

[0022] [fig.lb] Figure lb is a detailed perspective view of a seat cushion according to the invention provided with inserts seen by transparency;

Figure 1c is a longitudinal sectional view of the seat cushion according to the invention;

Figure Id is a cross-sectional view of the seat cushion according to the invention;

Figure 2 shows curves obtained for different types of inserts during compression tests of the seat cushion;

[0026] [fig.3a] Figure 3a shows a cross-sectional view of a first type of insert according to the state of the art subjected to the compression test;

[0027] [fig.3b] Figure 3b shows a cross-sectional view of a second type of insert according to the invention subjected to the compression test;

[0028] [fig.3c] Figure 3c shows a perspective and cross-sectional view of a third type of insert according to the invention subjected to the compression test;

[0029] [fig.4] Figure 4 is a graphical representation highlighting the optimal ratio between a thickness and a height of an insert to obtain the best ratio between the mechanical strength and the weight of the insert.

It should be noted that, in the figures, the structural and/or functional elements common to the different embodiments may have the same references.

Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

The relative terms of the "lower", "upper", "horizontal", "vertical" type are understood by reference to a seat and a seat cushion in the position of use, which corresponds to the orientations of the figures la and 1 hour in particular.

Figure la shows a seat 10, in particular an airplane seat, comprising a backrest 11 and a seat cushion 12 on which a passenger can sit.

The seat cushion 12 is mounted on two beams 13 belonging to a structure of the seat 10.

These beams 13 may consist of hollow beams made of a metallic material.

As can be seen in Figures 1h, lc, and Id, the seat cushion 12 comprises a lower foam layer 15 having a function of stiffening the seat cushion 12 and two upper foam layers 16.1, 16.2 having a seating comfort function.

To this end, the lower foam layer 15 is stiffer than the upper foam layers 16.1, 16.2.

The lower foam layer 15 may also have a greater density than the upper foam layers 16.1, 16.2.

The lower foam layer 15 and the upper foam layers 16.1, 16.2 are made of a plastic material.

According to a particular embodiment, the lower foam layer 15 is made of polyester and the upper foam layers 16.1, 16.2 are made of polyurethane.

Any other plastic material suitable for the application is possible.

The lower foam layer 15 and the upper foam layers 16.1, 16.2 are assembled together by gluing.

For this purpose, a solvent-based or water-based glue can be used.

Alternatively, the seat cushion 12 may comprise a single upper foam layer or more than two upper foam layers 16.1, 16.2.

[0036] A plurality of inserts 17 are arranged inside the lower foam layer 15.

For this purpose, the lower foam layer 15 may include grooves each intended to receive a corresponding insert 17.

The inserts 17 are arranged parallel to each other.

The inserts 17 have a direction of longitudinal elongation parallel to an axis X of the seat 10.

The X axis is a horizontal axis located in a median vertical plane of the seat 10.

The axis X of the seat 10 may be parallel to a longitudinal axis of the aircraft.

As a variant, the direction of longitudinal elongation of the inserts 17 may have a non-zero angle with the axis X of the seat 10.

The axis X of the seat 10 may also form a non-zero angle with the longitudinal axis of the aircraft.

In the example shown, four inserts 17 are provided.

Alternatively, it would of course be possible to provide a different number of inserts 17 inside the seat cushion 12.

In all cases, at least one insert 17 is placed inside the lower foam layer 15 of the seat cushion 12.

An insert 17 is preferably made of a metallic material and has a hollow tubular shape with a rectangular or square cross section.

Thus, the insert section 17 is closed.

Advantageously, an insert 17 is made of aluminum, in particular aluminum of the 7075-T6 type, or any other type of aluminum suitable for the application.

[0040] Figure 2 shows curves Cl -C3 of displacement D of the upper face of the seat cushion 12 obtained for different types of inserts 17 during a compression test of the seat cushion 12.

The curve Cl was obtained for an insert 17a having a cross-section in the shape of an omega shown in FIG. 3a and known from the state of the art.

The insert 17a has a length L of 320mm, a width 1 of 31mm, a height h of 11mm and a thickness c of 1.5mm.

A notch width Lc of the omega shape is 11.5 min

The curve C2 was obtained for an insert 17b having a rectangular section with right corners shown in Figure 3b.

The insert 17b has a length L of 320 mm, a cross-section of dimensions 1.20 mm x h=10 mm (1 being the width and h the height of the insert 17), and a thickness e of 1.5 mm In this case, the length L of an insert is measured along the X axis of the seat.

The width 1 of an insert is measured perpendicular to the length L in a horizontal plane.

The height h of an insert is measured in a vertical direction perpendicular to the length L and the width 1.

The C3 curve was obtained for an insert 17c having a rectangular section with rounded corners shown in Figure 3c.

The insert 17c has a length L of 320 mm a section of dimensions 1.20 mm x h=10 mm (1 being the width and h the height of the insert 17) and a thickness e of 1.5 mm A radius of curvature R at the level of the angles of the rectangle is 2mm.

The inserts 17b and 17c (cf. curves C2 and C3) having a rectangular section with straight or rounded corners are preferably selected which are more rigid under 6000N than the insert 17a with an omega-shaped section (cf. curve Cl).

The preferred dimensions adopted for the inserts 17b and 17c are of the order of those indicated above.

By "of the order of" is meant a variation of plus or minus 10% around the aforementioned values.

Furthermore, the table below shows that inserts 1711 and 17e having a rectangular section with straight or rounded corners better withstand a compression test of 107,000 cycles consisting of placing a weight of 100 kg at 1 cm from the cushion then release it and then start the operation again.

Simulation Simulation Simulation Criteria 17b 17c 17a % of the maximum stress 85% 81% acceptable by the 141% insert Plastic deformation of No No Yes the insert Post-impact deformation No No 1.4 mm of the insert (1 cycle)

[0046] Indeed, the inserts 17b and 17e with a rectangular section have a maximum acceptable stress percentage of less than 100% and no trace of plastic deformation, whereas this is not the case with the insert 17a with a shaped section. of omega.

[0047] It is also observed that there is no post-impact deformation with the rectangular inserts 17b, 17e whereas this deformation is 1.4 mm with the insert 17a with an omega-shaped section.

According to an advantageous embodiment, the insert 17b or 17e has a cross section identical to that of a luggage stop bar of an airplane seat 10.

In other words, for an airplane seat 10 according to the invention comprising a seat and a luggage stop bar, the insert(s) 17b or 17e of the seat cushion 12 and the luggage stop bar have identical rectangular sections .

The inserts 17 and the luggage stop bar can thus be obtained from the same profile, which makes it possible to make economies of scale by reducing the unit cost of an insert 17b or 17e.

11 should also be noted that in the case of the application of a vertical force on the seat cushion 12, the two most important dimensions allowing the insert 17b or 17e to resist the force are the thickness e as well as the height h of the insert 17h or 17e which extends vertically.

These two dimensions h and e must be chosen so as to optimize the mechanical strength while limiting the weight of the insert 17h or 17e.

As illustrated by FIG. 4, an optimal ratio R opt between a thickness e of the insert 17b or 17e divided by a height h of the insert 17b or 17e is between 0.10 and 0.19, and is equal to preference of the order of 0.15.

This optimal ratio range 6 R opt makes it possible to obtain a ratio (maximum bearable effort Eff in Newtons divided by a weight P of the insert in grams) of between 75 and 85.

[0051] Obviously, 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 consider in the context of the present invention and in particular all combinations of the various modes of operation described previously, which may be taken separately or in combination. 7

Claims (1)

CLAIMS [Claim 1] Seat cushion (12) for a vehicle seat (10), in particular an airplane seat, comprising: - at least one bottom layer of foam (15) having a function of stiffening said seat cushion seat (12), - at least one upper foam layer (16.1, 16.2) having a seating comfort function, and - at least one insert (17b, 17c) arranged inside the lower foam layer ( 15), characterized in that the insert (17b, 17c) is made of a metallic material and has a hollow tubular shape with a rectangular or square cross section. [Claim 2] Seat cushion according to Claim 1, characterized in that the insert (17b, 17c) is made of aluminium. [Claim 3] Seat cushion according to claim 1 or 2, characterized in that the insert (176) has a rectangular section with straight corners. [Claim 4] Seat cushion according to claim 1 or 2, characterized in that the insert (17c) has a rectangular section with rounded corners. [Claim 5] Seat cushion according to any one of Claims 1 to 4, characterized in that a ratio (R_opt) between a thickness (e) of the insert (17b, 17c) divided by a height (h) of the insert (17b, 17c) is between 0.10 and 0.19, and is preferably around 0.15. [Claim 6] Seat cushion according to any one of Claims 1 to 5, characterized in that the lower layer of foam (15) and the upper layer of foam (16.1, 16.2) are assembled together by gluing . [Claim 7] Seat cushion according to any one of claims 1 to 6, characterized in that it comprises a plurality of inserts (17b, 17c), in particular four inserts (17b, 17c), arranged parallel one to another. [Claim 8] Seat cushion according to any one of Claims 1 to 7, characterized in that the lower layer of foam (15) and the upper layer of foam (16.1, 16.2) are made of a plastic material . [Claim 9] Seat cushion according to any one of Claims 1 to 8, characterized in that the lower layer of foam (15) is made of polyester. [Claim 10] Seat cushion according to any one of Claims 1 to 9, ca- 8 [Claim 11] [Claim 12] [Claim 13] [Claim 14] characterized in that the upper foam layer (16.1, 16.2) is made of polyurethane. Seat cushion according to any one of Claims 1 to 10, characterized in that the insert (17b, 17c) has a section with dimensions of the order of 10 mm x 20 mm and a thickness (e) of the order of 1.5mm. Seat cushion according to any one of Claims 1 to 11, characterized in that the insert (1711, 17c) has a cross-section identical to that of a luggage stop bar of an airplane seat. Aircraft seat (10) including a seat cushion (12) as defined in any preceding claim. Airplane comprising a seat (10) as defined according to the preceding claim.