WO2020234115A1

WO2020234115A1 - Seat cushion provided with at least one stiffening insert

Info

Publication number: WO2020234115A1
Application number: PCT/EP2020/063491
Authority: WO
Inventors: Martin GUILLERAULT; Jérémy Cailleteau
Original assignee: Safran Seats
Priority date: 2019-05-22
Filing date: 2020-05-14
Publication date: 2020-11-26
Also published as: FR3096342B1; FR3096342A1

Abstract

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

Description

Title of the invention: SEAT CUSHION WITH AT LEAST ONE

RIGIDIFICATION INSERT

[0001] The present invention relates to a seat cushion provided with at least one stiffening insert. The invention finds a particularly advantageous application with aircraft seats.

[0002] In a manner known per se, seat cushions may include stiffening inserts arranged inside a layer of foam. These inserts can be made from a composite material or from a metallic material. Document US2009 / 0055023 thus describes inserts of round or omega-shaped section inserted into 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 that the inserts will break or bend after a few years of use, so the replacement of the seat should be done sooner than expected.

The invention aims to effectively remedy this drawback by providing a seat cushion for a vehicle seat, in particular an aircraft seat, comprising:

- at least one lower foam layer having a function of stiffening said seat cushion,

- at least one upper layer of foam having a seat 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 of rectangular or square cross section.

[0005] 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 premature 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 right corners.

[0008] According to one embodiment, the insert has a rectangular section with rounded corners.

[0009] 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 preferably is of the order of 0.15.

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

[001 1] According to one embodiment, said seat cushion comprises a plurality of inserts, in particular four inserts, arranged parallel to each other.

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

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

[0014] According to one embodiment, the upper foam layer is made of polyurethane.

[0015] According to one embodiment, the insert has a section of dimensions of the order of 10mm x 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 aircraft seat.

[0017] The subject of the invention is also an aircraft seat comprising a seat cushion as defined above. [0018] The invention further relates to an aircraft comprising a seat as defined above.

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 non-examples. limiting, which may serve to complete the understanding of the present invention and the description of its implementation and, where appropriate, contribute to its definition, on which:

[0021] [Fig. 1 a] FIG. 1 a is a perspective view of an airplane seat according to the invention comprising a seat cushion provided with inserts seen by transparency;

[0022] [Fig. 1 b] Figure 1 b is a detailed perspective view of a seat cushion according to the invention provided with inserts seen through transparency;

[0023] [Fig. 1 c] Figure 1 c is a longitudinal sectional view of the seat cushion according to the invention;

[0024] [Fig. 1 d] Figure 1 d is a cross-sectional view of the seat cushion according to the invention;

[0025] [Fig. 2] Figure 2 shows the curves obtained for different types of inserts during compression tests of the seat cushion;

[0026] [Fig. 3a] FIG. 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] FIG. 3b shows a cross-sectional view of a second type of insert according to the invention subjected to the compression test; [0028] [Fig. 3c] FIG. 3c shows a perspective view in cross section of a third type of insert according to the invention subjected to the compression test;

[0029] [Fig. 4] FIG. 4 is a graphic representation showing the optimum ratio between a thickness and a height of an insert making it possible to obtain the best ratio between the mechanical strength and the weight of the insert.

[0030] 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 type "lower", "upper", "horizontal", "vertical" are understood by reference to a seat and a seat cushion in the position of use, which corresponds to the orientations of Figures 1 a and 1 b in particular.

Figure 1 a shows a seat 10, in particular an aircraft seat, comprising a backrest 1 1 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 be constituted by hollow beams made of a metallic material.

As can be seen in Figures 1 b, 1 c, and 1 d, the seat cushion 12 comprises a lower foam layer 15 having a function of stiffening the seat cushion 12 and two layers of foam upper 16.1, 16.2 having a seating comfort function. To this end, the lower foam layer 15 is more rigid 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 aqueous-based adhesive can be used. As a variant, the seat cushion 12 may comprise a single layer of upper foam or more than two upper layers of foam 16.1, 16.2.

A plurality of inserts 17 are arranged inside the lower foam layer 15. For this purpose, the lower foam layer 15 may have 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 axis X is a horizontal axis lying in a vertical median 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 present a non-zero angle with the X axis of the seat 10. The X axis of the seat 10 may also form a non-zero angle with the longitudinal axis of the aircraft. .

In the example shown, there are four inserts 17. As a variant, it would of course be possible to provide a different number of inserts 17 inside the seat cushion 12. In all cases, at least an 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 of rectangular or square cross section. Thus, the section of the insert 17 is closed. Advantageously, an insert 17 is made of aluminum, in particular an aluminum of the 7075-T6 type, or any other type of aluminum suitable for the application.

[0040] Figure 2 shows curves C1 -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 C1 was obtained for an insert 17a having an omega-shaped cross section shown in Figure 3a and known from the state of the technical. The insert 17a has a length L of 320mm, a width I of 31 mm, a height h of 11 mm and a thickness e of 15 mm. A width Le of the notch of the omega shape is 11 5mm.

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 l = 20mm x h = 10mm (I being the width and h the height of the insert 17), and a thickness e of 1.5mm. In this case, the length L of an insert is measured along the axis X of the seat. The width I 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 to the width I.

The curve C3 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 l = 20mm x h = 10mm (I being the width and h the height of the insert 17) and a thickness e of 1.5mm. A radius of curvature R at the angles of the rectangle is 2mm.

Preferably selects the inserts 17b and 17c (cf. curves C2 and C3) having a rectangular section with right or rounded corners which are more rigid under 6000N than the insert 17a with an omega-shaped section (cf. curve C1). The preferred dimensions retained for inserts 17b and 17c are of the order of those indicated above. By "order of" is meant a variation of plus or minus 10% around the above values.

Moreover, the table below shows that the inserts 17b and 17c having a rectangular section with right or rounded corners better withstand a compression test of 107,000 cycles consisting of having a weight of 100kg at 1 cm from the cushion then let go and then start the operation again.

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

It is also observed that there is no post-impact deformation with the rectangular inserts 17b, 17c while this deformation is 1 4mm with the insert 17a with an omega-shaped section.

According to an advantageous embodiment, the insert 17b or 17c has a cross section identical to that of a luggage stop bar of an aircraft seat 10. In other words, for an aircraft seat 10 according to the invention comprising a seat and a baggage stop bar, the insert or inserts 17b or 17c of the seat cushion 12 and the luggage stop bar have identical rectangular sections. The inserts 17 and the baggage stop bar can thus be obtained from the same section, which makes it possible to make economies of scale by reducing the unit cost of an insert 17b or 17c.

It 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 17c to resist the force are the thickness e as well as the height h of the insert 17b or 17c 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 17b or 17c. As illustrated by Figure 4, an optimal ratio R_opt between a thickness e of the insert 17b or 17c divided by a height h of the insert 17b or 17c is between 0.10 and 0.19, and is preferably of the order of 0.15. This optimal ratio range 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.

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 which 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 described above, which may be taken separately or in combination.

Claims

Claims)

[Claim 1] Seat cushion (12) for a vehicle seat (10), in particular an aircraft seat, comprising:

- at least one lower foam layer (15) having a function of stiffening said seat cushion (12),

- at least one upper foam layer (16.1, 16.2) having a seat 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 of rectangular or square cross section.

[Claim 2] A seat cushion according to claim 1, characterized in that the insert (17b, 17c) is made of aluminum.

[Claim 3] A seat cushion according to claim 1 or 2, characterized in that the insert (17b) has a rectangular section with right corners.

[Claim 4] A seat cushion according to claim 1 or 2, characterized in that the insert (17c) has a rectangular section with rounded corners.

[Claim 5] A 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 of the order of 0.15.

[Claim 6] A seat cushion according to any one of claims 1 to 5, characterized in that the lower foam layer (15) and the upper foam layer (16.1, 16.2) are assembled together by gluing.

[Claim 7] A 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 to each other compared to others.

[Claim 8] A seat cushion according to any one of claims 1 to 7, characterized in that the lower foam layer (15) and the upper foam layer (16.1, 16.2) are made of a plastic material.

[Claim 9] A seat cushion according to any one of claims 1 to 8, characterized in that the lower foam layer (15) is made of polyester.

[Claim 10] A seat cushion according to any one of claims 1 to 9, characterized in that the upper foam layer (16.1, 16.2) is made of polyurethane.

[Claim 1 1] seat cushion according to any one of claims 1 to 10, characterized in that the insert (17b, 17c) has a section of dimensions of the order of 10mm x 20mm and a thickness (e ) of the order of 1 5mm.

[Claim 12] A seat cushion according to any one of claims 1 to 1 1, characterized in that the insert (17b, 17c) has a cross section identical to that of a luggage stop bar of a airplane seat.

[Claim 13] An aircraft seat (10) comprising a seat cushion (12) as defined in any one of the preceding claims.

[Claim 14] An airplane comprising a seat (10) as defined in the preceding claim.