Extendable vehicle seat cushion

Abstract

Extendable vehicle seat The vehicle seat (1) comprises a main seat portion (2) and a movable seat portion (4) sliding on a frame (6) between a retracted position and an extended position, the seat (1) further comprising a cover element (36) extending between the main seat portion (2) and the movable seat portion (4), said cover element (36) being movable between a retracted position and an extended position, in which the cover element (36) fills the space between the main seat portion (2) and the movable seat portion (4) in the extension direction (E) when the movable seat portion (4) is in the extended position. The cladding element (36) is attached to the frame (6) by an elastic band (40), which exerts a restoring force on the cladding element (36) towards the retracted position when said cladding element (36) is in the deployed position. Figure for the abbreviation: 3

Description

Title of the invention: Extendable vehicle seat

[0001] The present invention relates to a vehicle seat, of the type comprising a main seat part and a movable seat part, movable relative to the main seat part in an extension direction between a retracted position, in which the movable seat part extends against the main seat part, and an extended position, in which the movable seat part is spaced from the main seat part in the extension direction, said movable seat part sliding on a frame between the retracted position and the extended position, said frame extending in the extension direction between a rear edge extending opposite the main seat part and a front edge extending opposite the movable seat part and spaced from the main seat part in the extension direction,the seat further comprising a covering element extending between the main seat portion and the movable seat portion, said covering element being movable between a retracted position, in which the covering element is folded between the main seat portion and the movable seat portion when the movable seat portion is in the retracted position, and an extended position, in which the covering element fills the space between the main seat portion and the movable seat portion in the extension direction when the movable seat portion is in the extended position.

[0002] Vehicle seats are known, particularly for motor vehicles, in which the seat is made in two parts, one of which is movable relative to the other in order to allow the seat surface to be extended when the movable seat part is in an extended position.

[0003] The movable seat part, also known as the seat nose, provides support for the fore-thighs of a seat occupant to improve seat comfort and in particular to reduce fatigue on long journeys.

[0004] Moving the movable seat portion to the extended position creates a gap between the main seat portion and the movable seat portion, and it is known to fill this gap by means of a covering element that allows the continuity of the seat surface to be maintained, the covering element extending in continuity with the seat surfaces of the main and fixed seat portions. When the movable seat portion is in a retracted position, in which it extends against the main seat portion, the covering element is folded between the main seat portion and the movable seat portion so as to extend into the thickness of the seat and to be invisible from outside the seat.

[0005] In order to preserve the comfort and appearance of the seat when the movable seat part is in the retracted position, it is necessary to ensure that the covering element folds correctly between the main seating part and the movable seating part when the movable seating part moves from its extended position to its retracted position. To achieve this, it is provided that the movable seating part causes the covering element to move from its extended position to its retracted position when the movable seating part moves from its extended position to its retracted position.

[0006] However, such a drive requires a complex connecting device between the carriage or drawer moving the movable seat part and the covering element. Furthermore, such a connecting device generally does not ensure effective pressing of the covering element against the main seat part in the retracted position, which can hinder the return of the movable seat part to its retracted position and prevent the movable seat part from being locked in this retracted position. The quality perceived by the occupant of the seat is then degraded.

[0007] One of the aims of the invention is to overcome these drawbacks by proposing a vehicle seat base comprising a movable seat part and a covering element having satisfactory comfort and appearance in all positions of the movable seat part.

[0008] To this end, the invention relates to a vehicle seat base of the aforementioned type, in which the covering element is fixed to the frame, in the vicinity of the rear edge of said frame, by at least one elastic band, said elastic band exerting a restoring force on the covering element towards the retracted position, when said covering element is in the deployed position.

[0009] By fixing the covering element to the seat frame by an elastic band at a location on the frame extending opposite the main seat portion, the restoring force exerted by the elastic band ensures good pressing of the covering element against the main seat portion in the retracted position of the covering element, which ensures good positioning of the movable seat portion in the retracted position. In addition, the connection between the covering element and the movable seat portion can be simplified, which simplifies the structure of the seat as a whole.

[0010] The vehicle seat base according to the invention may comprise one or more of the following characteristics, taken individually or in any technically conceivable combination: - the covering element extends between a rear edge secured to the main seat part and a front edge secured to the movable seat part, the elastic band being fixed to the covering element in the vicinity of the front edge of the covering element and being elastically stretched when the covering element passes from the retracted position to the deployed position; - the elastic band is fixed directly to the frame by at least one fixing pin passing through the elastic band and anchored in the frame; - the elastic band is engaged in a slot of a rod fixed to the covering element and is fixed by its two ends to a fixing element, said fixing element being fixed to the frame; - the fixing element is formed by a profile extending between two transverse edges, the ends of the elastic band being fixed on an upper face of said profile between the transverse edges, said profile being fixed to the frame by fixing pins passing through the profile at its transverse edges, a lower face of the profile, opposite the upper face, being applied against the frame; - the covering element is fixed to the frame by two elastic bands spaced apart from each other in a transverse direction substantially perpendicular to the direction of extension; - the two elastic bands are fixed to the same fixing element, said fixing element being formed by a rod fixed to the frame of the seat; - the covering element is made in one piece with a cover of the main seating part, said covering element folding along a fold line extending between the cover and the covering element from the deployed position to the retracted position; - the covering element is attached to the movable seat portion such that movement of the movable seat portion from the retracted position to the extended position causes movement of the covering element from the retracted position to the extended position; - the movable seat part comprises a carriage mounted so as to move in translation on the frame, said carriage moving in the direction of extension in a direction going from the rear edge to the front edge of the frame when the movable seat part moves from the retracted position to the extended position; - the elastic band has an elongation at break greater than or equal to 120%.

[0011] Other aspects and advantages of the invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0012] [Fig.l] - [Fig.l] is a schematic perspective representation of a vehicle seat base according to the invention, the movable seat part being in the retracted position,

[0013] [Fig.2] - [Fig.2] is a schematic perspective representation of the seat base of vehicle seat of [Fig.l], the movable seat part being in the extended position,

[0014] [Fig.3] - [Fig.3] is a schematic sectional representation of the seat base of vehicle of [Fig.l], the movable seat part being in the retracted position,

[0015] [Fig.4] - [Fig.4] is a schematic perspective representation of the interior of a vehicle seat base according to an embodiment of the invention, the movable seat part being disassembled from the seat frame,

[0016] [Fig.5] - [Fig.5] is an exploded schematic representation of the device for connecting the covering element to the seat frame of [Fig.4], and

[0017] [Fig.6] - [Fig.6] is an exploded schematic representation of a device for connecting the covering element to the seat frame according to another embodiment of the invention.

[0018] With reference to Figs 1 to 3, a vehicle seat is described comprising a seat 1 comprising a main seat part 2 and a movable seat part 4 mounted on a frame 6. The vehicle seat is for example a motor vehicle seat, in particular a front seat of a motor vehicle. It is however understood that the vehicle seat according to the invention can be used in other types of vehicles, for example maritime or air.

[0019] The main seating portion 2 is fixedly mounted on the frame 6, i.e. it does not move relative to the latter. The main seating portion 2 is conventionally formed from padding 8 covered by a cover 10, the outer surface 12 of the cover 10 forming a main seating surface for an occupant of the seat. The main seating portion 2 forms the part of the seating 1 which is adjacent to the back of the vehicle seat. Thus, the main seating portion 2 is the part of the seating which extends furthest to the rear of the vehicle seat when the vehicle seat is facing the front of the vehicle in which it is installed. In the description, the terms "front" and "rear" are defined relative to an extension direction E, corresponding to the front-rear direction of a vehicle when the vehicle seat is facing the front of the vehicle.The main seat part 2 thus extends between a rear edge 16 adjacent to the backrest and a front edge 18 spaced from the rear edge 16 in the direction of extension E. The front 16 and rear 18 edges extend in a transverse direction substantially perpendicular to the direction of extension E and corresponding to the width of the vehicle in which the vehicle seat is installed. The thickness of the main seat part 2 is measured in an elevation direction substantially perpendicular to the direction of extension E and to the transverse direction and corresponds to the addition of the thickness of the padding 8 and the cover 10.

[0020] The movable seat part 4, also known as the seat nose, is movably mounted on the frame 6, i.e. it can move on the frame 6 and relative to the main seat part 2. More particularly, the movable seat part 4 is movable in the extension direction E between a position retracted (Figs. 1 and 3) and an extended position ([Fig.2]), as will be described in more detail later. The movable seat part 4 also comprises a padding 20 covered by a cover 22, the outer surface 24 of which forms a complementary seating surface for the occupant of the seat. Thus, the main seating surface and the complementary seating surface together form the complete seating surface of the seat 1 of the vehicle seat. For this purpose, the external surface 24 of the movable seat part 4 extends substantially in continuity with the external surface 12 of the main seat part 2. The movable seat part 4 forms the part of the seat 1 which is adjacent to the main seat part 2 in front of the latter in the direction of extension E. Thus, the movable seat part 4 is the part of the seat which extends furthest forward of the vehicle seat when the vehicle seat is turned towards the front of the vehicle in which it is installed.The movable seat part 4 extends between a rear edge 26 adjacent to the front edge 18 of the main seat part 2 and a front edge 28 spaced from the rear edge 26 in the direction of extension E, the rear edges 26 and front 28 extending in the transverse direction. The thickness of the movable seat part 4, measured in the direction of elevation, corresponds to the addition of the thickness of the padding 20 and the cover 22.

[0021] In the retracted position, the movable seat part 4 extends against the main seat part 2, i.e. the rear edge 26 of the movable seat part 4 is applied against the front edge 18 of the main seat part 2, as shown in Figs. 1 and 3. In the extended position, the movable seat part 4 is spaced from the main seat part 2 in the extension direction E, i.e. there is a gap between the rear edge 26 of the movable seat part 4 and the front edge 18 of the main seat part 2, this gap extending in the extension direction E. In other words, in the extended position, the complete seating surface of the seat 1 is larger than the complete seating surface of the seat in the retracted position.

[0022] The movement of the movable seat part 4 between the retracted position and the extended position is a translational movement of the movable seat part 4 on the frame 6 in the extension direction E. More particularly, the passage from the retracted position to the extended position is a forward translational movement of the movable seat part 4 on the frame 6 and the passage from the extended position to the retracted position is a rearward translational movement of the movable seat part 4 on the frame 6. To allow these movements of the movable seat part 4, the latter comprises a carriage 30, also known as a drawer, slidably mounted on the frame 6, more particularly on one or more rails (not shown) integral with the frame 6 and extending in the extension direction E. The carriage 30 extends in the padding 20 of the movable seat part 4.

[0023] The frame 6 extends in particular between a rear edge 32 and a front edge 34, extending in the transverse direction and spaced apart from each other in the extension direction E. As shown in [Fig.4], the frame 6 is for example formed by a metal plate extending between the rear edge 32 and the front edge 34, this metal plate receiving the movable seat part 4 and allowing the latter to move between the retracted position and the extended position.

[0024] The rear edge 32 of the frame 6 extends opposite the main seat part 2. More particularly, the rear edge 32 of the frame 6 extends, for example, opposite or in the vicinity of the front edge 18 of the main seat part 2. By “opposite or in the vicinity”, it is meant that the rear edge 32 of the frame 6 extends substantially at the same level as the front edge 18 of the main seat part 2 in the direction of extension E. Thus, the position of the rear edge 32 of the frame 6 corresponds substantially to the position of the rear edge 26 of the movable seat part 4 when the movable seat part 4 is in the retracted position.

[0025] The front edge 34 of the frame 6 extends opposite the movable seat portion 4 in all positions of the movable seat portion 4. More particularly, the front edge 34 of the frame 6 extends opposite or in the vicinity of the front edge 28 of the movable seat portion 4 when the movable seat portion 4 is in the retracted position and between the rear edge 26 and the front edge 28 of the movable seat portion 4 when the movable seat portion 4 is in the extended position. Thus, in the extended position, a portion of the movable seat portion 4 projects forward from the frame 6 in the extension direction E, as seen in [Fig. 2].

[0026] According to one embodiment, the distance between the rear edge 32 and the front edge 34 of the frame 6 is substantially equal to the distance between the rear edge 26 and the front edge 38 of the movable seat part 4, as visible in [Fig. 3]. Alternatively, the distance between the rear edge 26 and the front edge 38 of the movable seat part 4 is slightly greater than the distance between the rear edge 32 and the front edge 34 of the frame 6.

[0027] The seat 1 further comprises a locking device, not shown, making it possible to lock the movable seat part 4 in the retracted position and in the extended position, the locking device being actuated, for example by means of a handle, by the occupant of the seat to allow the positioning of the movable seat part 4 in the desired position. According to one embodiment, the movable seat part 4 can be positioned and locked in a plurality of intermediate positions between the retracted position and the extended position, the movable seat part 4 being more or less spaced from the main seat part 2 in these intermediate positions.

[0028] The seat 1 further comprises a covering element 36, or bellows, extending between the main seat part 2 and the movable seat part 4 in the direction extension direction E. More particularly, the covering element 36 is movable between a retracted position, visible in Figs. 3 and 4, in which the covering element is folded between the main seat part 2 and the movable seat part 4 when the movable seat part 4 is in the retracted position, and a deployed position, visible in [Fig. 2], in which the covering element 36 fills the space between the main seat part 2 and the movable seat part 4 in the extension direction E when the movable seat part 4 is in the extended position.

[0029] In the retracted position, the covering element 36 extends mainly in the elevation direction against the front edge 18 of the main seat part 2, as more particularly visible in [Fig. 3]. Thus, in the retracted position, the covering element 36 extends in the thickness of the seat 1 and is hidden inside the seat 1 so that it is not visible from the outside of the seat 1 when the movable seat part 4 is in the retracted position.

[0030] In the deployed position, the covering element 36 extends mainly in the direction of extension E between the front edge 18 of the main seat part 2 and the rear edge 26 of the movable seat part 4, substantially in the continuity of the main seat surface and the complementary seat surface so that the complete seat surface of the seat 1 is continuous and the passengers of the vehicle do not see the space extending between the main seat part 2 and the movable seat part 4 from outside the seat 1 when the movable seat part 4 is in the extended position. The covering element 36 extends between a rear edge 37 secured to the main seat part 2, more particularly the front edge 18 of the main seat part 2 at the level of the cover 10 of the main seat part 2, and a front edge 38 spaced from the rear edge 37 and secured to the movable seat part 4.

[0031] According to one embodiment, the covering element 36 is made in one piece with the cover 10 of the main seat part 2. Thus, the covering element 36 is for example formed by an extension of the cover 10 extending beyond the padding 8 of the main seat part 2 in the extension direction E, this extension of the cover 10 being folded along a fold line, extending between the cover 10 and the covering element 36 in the transverse direction, from the deployed position to the retracted position. The fold line then forms the rear edge 37 of the covering element 36.In the deployed position, the extension of the cover 10 extends the outer surface 12 of the cover 10 in the extension direction E to the rear edge 26 of the movable seat part 4 and, in the retracted position, the extension of the cover 20 is folded against the front edge 18 of the main seat part 2 and extends substantially in the elevation direction. The covering element 36 thus extends from the fold line to the front edge 38. In the deployed position, the front edge 38 extends against the rear edge 26 of the movable seat part 4 at . level of the cover 22 of the movable seat part 4 so that the covering element 36 forms a continuous surface with the external surfaces 12 and 24 of the main 2 and movable 4 seat parts. In the retracted position, the front edge 38 is brought closer to the frame 6, as more particularly visible in [Fig.4].

[0032] The covering element 36 is for example connected to the movable seat part 4 so that the movement of the movable seat part 4 between the retracted position and the extended position causes the movement of the covering element 36 from the retracted position to the deployed position. Conversely, the movement of the movable seat part 4 from the extended position to the retracted position also causes that of the covering element 36 from the deployed position to the retracted position, but this movement of the covering element 36 is assisted by at least one elastic band 40, which makes it possible to simplify the connection between the covering element 36 because the pressing of the covering element 36 against the front edge 18 of the main seat part 2 is ensured by the elastic band 40, as will now be described.

[0033] The elastic band 40 is fixed on the one hand to the covering element 36 and on the other hand to the frame 6, in the vicinity of the rear edge 32 thereof. The elastic band 40 is arranged to be stretched elastically when the covering element 36 passes from the retracted position to the deployed position and to exert a restoring force on the covering element tending to bring the covering element 36 back to its retracted position. Thus, by elastic, it is meant that the elastic band 40 can be stretched and elongated in the direction in which the elastic band 40 extends so as to increase its length and that it returns to its initial length when the force stretching the elastic band 40 ceases to be applied thereto.The elastic band 40 has, for example, an elongation at break greater than or equal to 120%, for example substantially between 120% and 350%, which means that the elastic band 40 can be stretched until it has a length between 120% and 350% of its length when it is not stressed before breaking. According to a particular embodiment, the elastic band 40 has an elongation at break close to 300%. According to one embodiment, the elastic band has a maximum tension greater than or equal to 300 N, for example substantially between 300 N and 500 N. According to one embodiment, the force necessary to lengthen the elastic band by 50% is substantially between 9 N and 17 N, for example substantially equal to 13 N. According to one embodiment, the elastic band 40 has a linear mass substantially between 14 gm 1 and 21 gm ', for example substantially equal to 17.8 gm '.The elastic band 40 has, for example, a length of between 60 mm and 100 mm, for example substantially equal to 80 mm, which means that the elastic band 40 can be stretched to a length of between 180 mm and 300 mm, for example 240 mm, before breaking. The elastic band 40 has, for example, a . width substantially between 15 mm and 25 mm, for example substantially equal to 20 mm. The elastic band 40 is for example composed of natural rubber and polyester (PES) fibers, the proportion of natural rubber fibers being for example greater than that of PES fibers. According to one embodiment, between the proportion of PES is substantially between 40 and 50% and the proportion of natural rubber is substantially between 50% and 60%, for example 44% PES and 56% natural rubber.

[0034] As shown in Figs. 4 to 6, the elastic band 40 is for example engaged in a slot 42 of a rod 44 and its two ends 46 are fixed to a fixing element 48.

[0035] The rod 44 is fixed to the covering element 36 in the vicinity of its front edge 38 and extends along the front edge 38 in the transverse direction. More particularly, the rod 44 is for example sewn into a bead of the covering element 36 forming the front edge 38 of the covering element 36, as shown in [Fig. 4].

[0036] According to the embodiment shown in Figures 4 to 6, the covering element 36 is fixed to the frame 6 by two elastic bands 40 each fixed in the vicinity of one end of the front edge 38 of the covering element 36 in the transverse direction. Thus, the two elastic bands 40 are spaced from each other in the transverse direction. According to this embodiment, the rod 44 comprises two slots 42 each extending at the transverse ends of the rod 44, as seen in Figs. 5 and 6, each elastic band 40 passing through one of the slots 42.

[0037] According to the embodiment shown in Figs. 4 and 5, the fixing element 48 is formed by a profile 50 fixed by fixing pins 52 to the rear edge 32 of the frame 6. When the covering element 36 is fixed to the frame 6 by two elastic bands 40, each elastic band 40 is fixed to the frame 6 by a profile 50, that is to say that two profiles 50 are fixed to the rear edge 32 of the frame 6. The or each profile 50 is formed by a substantially rectangular plate extending mainly in the transverse direction and the two ends 46 of the elastic band 40 are fixed, for example sewn, to an upper face of the profile 50 and a lower face of the profile 50, opposite the upper face, is applied against the frame 6, as visible in [Fig.4].The profile 50 comprises, in the vicinity of its transverse ends, two through orifices 54 opening into the upper face and into the lower face, the fixing pins 52 passing through the orifices 54 to fix the profile 50 to the frame 50. The fixing pins 52 are for example fir tree pins anchored in the metal plate forming the frame 6. The profile 50 is formed from a rigid material, capable of resisting the restoring force exerted by the elastic band 40. Thus, the profile 50 remains integral with the frame 6 even when it is . stressed by the restoring force of the elastic band 40.

[0038] Alternatively, the or each elastic band 40 is fixed directly to the frame 6 by at least one fixing pin 52, such as a fir-tree pin. In this case, the fixing pin 52 passes through the elastic band 40 and is anchored in the frame 6 to fix the end of the elastic band 40 directly to the frame 6. The elastic band 40 is for example fixed by one, two or three fixing pins 52 to the frame.

[0039] The distance d between the center of the ends of the elastic bands 40 fixed to the frame 6, shown in [Fig. 4], is for example substantially between 200 mm and 285 mm. More particularly, when the elastic bands 40 are fixed to the frame 6 by means of profiles 50, the distance d is between 200 mm and 250 mm and when the elastic bands 40 are fixed to the frame 6 directly by fixing pins 52, the distance d is between 250 mm and 285 mm.

[0040] According to another embodiment shown in [Fig.6], the fixing element 48 is formed by a rod 56 extending in the transverse direction. Thus, when the covering element 36 is fixed to the frame 6 by two elastic bands 40, each elastic band 40 is fixed to the frame 6 by the same fixing element 48 formed by the rod 56. The ends 46 of the elastic bands 40 are for example sewn in the vicinity of the transverse ends of the rod 56. The rod 56 is for example fixed to the rail(s) allowing the movement of the carriage 30 of the movable seat part 40. The fixing of the elastic bands 50 to the rod 56 makes the fixing between the elastic bands 40 and the frame 6 more robust, the rod 56 resisting the stresses of the elastic bands 40 better than the profiles 50 when the elastic bands 40 are stretched by the covering element 36 in the deployed position.

[0041] Regardless of the embodiment, the fixing element(s) 48 enabling the elastic band(s) 40 to be fixed to the frame 6 are fixed to the frame 6 so that the covering element 36 extends substantially in the elevation direction against the front edge 18 of the main seat portion 2 when the covering element 36 is in the retracted position, as more particularly visible in [Fig. 3]. In the retracted position, the elastic band(s) 40 also extend substantially in the elevation direction or slightly rearward so that the ends 46 are fixed to the frame 6 substantially in line with the front edge 18 of the main seat portion 2 in the elevation direction, as shown in Figs. 3 and 4.

[0042] Thus, when the covering element 36 is moved from the deployed position to the retracted position when the movable seat part 4 is moved from the extended position to the retracted position, the elastic band(s) 40, due to the restoring force that they exert on the covering element 36, returns the covering element 36 to the retracted position and ensures that the covering element 36 is pressed against the front edge 18 of the main seat part 2, thus ensuring that the covering element 36 is correctly positioned in the retracted position, in particular so that the movable seat part 4 can reach its retracted position without difficulty.

[0043] Thus, the movement of the covering element 36 to the retracted position is simplified and reliable, the connection between the covering element 36 and the movable seat part 4 can also be simplified because the movement of the covering element 36 to the retracted position is mainly obtained by the restoring force of the elastic band(s) 40, rather than by a complex connection device between the covering element 36 and the movable seat part 4.

Claims

Claims

1. A vehicle seat (1) comprising a main seat portion (2) and a movable seat portion (4), movable relative to the main seat portion (2) in an extension direction (E) between a retracted position, in which the movable seat portion (4) extends against the main seat portion (2), and an extended position, in which the movable seat portion (4) is spaced from the main seat portion (2) in the extension direction (E), said movable seat portion (4) sliding on a frame (6) between the retracted position and the extended position, said frame (6) extending in the extension direction (E) between a rear edge (32) extending opposite the main seat portion (2) and a front edge (34) extending opposite the movable seat portion (4) and spaced from the main seat portion (2). main seat (2) according to the direction of extension (E),the seat (1) further comprising a covering element (36) extending between the main seat part (2) and the movable seat part (4), said covering element (36) being movable between a retracted position, in which the covering element (36) is folded between the main seat part (2) and the movable seat part (4) when the movable seat part (4) is in the retracted position, and a deployed position, in which the covering element (36) fills the space between the main seat part (2) and the movable seat part (4) in the extension direction (E) when the movable seat part (4) is in the extended position, characterized in that the covering element (36) is fixed to the frame (6), in the vicinity of the rear edge (32) of said frame (6), by at least one elastic band (40), said elastic band (40) exerting a restoring force on the covering element (36) towards the retracted position,when said covering element (36) is in the deployed position.,

2. A vehicle seat cushion according to claim 1, wherein the covering element (36) extends between a rear edge secured to the main seating portion (37) and a front edge (38) secured to the movable seating portion (4), the elastic band (40) being secured to the covering element (36) in the vicinity of the front edge (38) of the covering element (36) and being elastically stretched when the covering element (36) moves from the retracted position to the extended position.

3. A vehicle seat cushion according to claim 1 or 2, wherein the elastic band (40) is fixed directly to the frame (6) by at least one fixing pin (52) passing through the elastic band (40) and anchored in the frame (6).

4. A vehicle seat base according to claim 1 or 2, wherein the elastic band (40) is engaged in a slot (42) of a rod (44) fixed to the covering element (36) and is fixed by its two ends (46) to a fixing element (48), said fixing element (48) being fixed to the frame (6).

5. Vehicle seat base according to claim 4, in which the fixing element (48) is formed by a profile (50) extending between two transverse edges, the ends (46) of the elastic band (40) being fixed on an upper face of said profile (50) between the transverse edges, said profile (50) being fixed to the frame (6) by fixing pins (52) passing through the profile (50) at its transverse edges, a lower face of the profile (50), opposite the upper face, being applied against the frame (6).

6. Vehicle seat base according to any one of claims 1 to 5, in which the covering element (36) is fixed to the frame (6) by two elastic bands (40) spaced from each other in a transverse direction substantially perpendicular to the direction of extension (E).

7. A vehicle seat base according to claim 6, when dependent on claim 4, wherein the two elastic bands (40) are attached to the same fixing element (48), said fixing element (48) being formed by a rod (56) attached to the seat frame.

8. A vehicle seat base according to any one of claims 1 to 7, wherein the covering element (36) is made in one piece with a cover (10) of the main seat part (2), said covering element (36) folding along a fold line extending between the cover (10) and the covering element (36) from the deployed position to the retracted position.

9. A vehicle seat cushion according to any one of claims 1 to 8, wherein the covering member (36) is attached to the movable seating portion (4) such that movement of the movable seating portion (4) from the retracted position to the extended position causes movement of the covering member (36) from the retracted position to the extended position.

10. A vehicle seat cushion according to any one of claims 1 to 9, in which the movable seat part (4) comprises a carriage (30) mounted movable in translation on the frame (6), said carriage (30) moving in the extension direction (E) in a direction going from the rear edge (32) towards the front edge (34) of the frame (6) when the movable seat part (4) moves from the retracted position to the extended position.

11. A vehicle seat cushion according to any one of claims 1 to 10, wherein the elastic band (40) has an elongation at break greater than or equal to 120%.

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