Motor vehicle seat headrest

Abstract

The invention relates to a headrest (1) for a motor vehicle seat comprising a secondary body (4) slidably mounted along a longitudinal direction (X) on a main body (3), said secondary body being provided with an upper tenon (6a) and a lower tenon (6b), each having a free end (8), and two upper (11a) and lower (11b) mortises for the respective sliding reception of said upper and lower tenons, said mortises being formed by molding said main body, such that each tenon (6a, 6b) and corresponding mortise (11a, 11b) forms a dovetail joint, said headrest further comprising a reinforcing cross member (13) connecting the free ends (8) of said tenons so as to stabilize their respective positioning relative to each other. Figure 2

Description

Title of the invention: Headrest for a motor vehicle seat

[0001] The invention relates to a headrest for a motor vehicle seat.

[0002] It is known, in particular from document FR-3 106 792, to produce a headrest of motor vehicle seat, said headrest comprising: • a mounting frame on a back of said seat, • a main body, made from molded plastic material, mounted on said frame, • a secondary body, made from molded plastic material, slidably mounted in a longitudinal direction on said main body to be able to adopt a plurality of adjustment positions, said secondary body being secured to a wall supporting the head of a passenger, said secondary body being provided with an upper tenon and a lower tenon facing each other along two opposite edges of said secondary body, said tenons each having an end connecting to the rest of said secondary body and a free end, said tenons having, when viewed in said longitudinal direction, a shape falling within a trapezoid having a large base facing inwards and a small base facing outwards, • two upper and lower mortises for receiving said upper and lower tenons in sliding manner, said mortises being produced by molding said main body, said mortises having a geometry complementary to that of said tenons and opening outwards through their small base, so that each tenon and corresponding mortise forms a dovetail type fixing.

[0003] With such an arrangement, guidance of the secondary body is ensured by means arranged in the peripheral zone of the headrest, which makes it possible to best control the correct sliding of said secondary body relative to the main body, with limitation of the phenomena of arching and / or impact of dimensional dispersions which are detrimental to said sliding and to the rigidity of the assembly.

[0004] However, it is difficult with such an arrangement to give the assembly good rigidity, which leads to the appearance of rotational play - particularly in transverse and vertical directions - when adjusting the secondary body.

[0005] This phenomenon may in particular result from the fact that the gap between the tenons may vary slightly, this being linked to the possibility for the secondary body, which is made of plastic material, to deform slightly when it is actuated.

[0006] The invention aims to overcome this drawback.

[0007] To this end, the invention proposes a headrest for a motor vehicle seat, said headrest including: • a mounting frame on a back of said seat, • a main body, made from molded plastic material, mounted on said frame, • a secondary body, made from molded plastic material, slidably mounted in a longitudinal direction on said main body to be able to adopt a plurality of adjustment positions, said secondary body being integral with a wall supporting the head of a passenger, said secondary body being provided with an upper tenon and a lower tenon facing each other along two opposite edges of said secondary body, said tenons each having an end connecting to the rest of said secondary body and a free end, said tenons having, when viewed in said longitudinal direction, a shape falling within a trapezoid having a large base facing inwards and a small base facing outwards, • two upper and lower mortises for receiving said upper and lower tenons in sliding manner, said mortises being produced by molding said main body, said mortises having a geometry complementary to that of said tenons and opening outwards through their small base, so that each tenon and corresponding mortise forms a dovetail type fixing,

[0008] said headrest further comprising a reinforcing crosspiece connecting the free ends of said tenons together so as to stabilize their respective positioning relative to each other.

[0009] In this description, the terms of positioning in space (top, bottom, upper, lower, longitudinal, transverse, lateral, vertical, horizontal, front, rear, etc.) are taken with reference to a reference point referring to the longitudinal (X), transverse (Y) and vertical (Z) directions in which the vehicle extends, the headrest being arranged in said vehicle in the use situation.

[0010] With the proposed arrangement, the blocking of the position of one tenon relative to the other is ensured by the installation of the reinforcing crosspiece.

[0011] This results in a notable improvement in the rigidity of the assembly and a very significant reduction in the clearances described above.

[0012] Other features and advantages of the invention will appear in the following description, given with reference to the attached figures, in which:

[0013] [Fig-1] is a simplified view in partial exploded perspective of a headrest according to an embodiment, the purpose of which is to illustrate the principle of sliding assembly of the secondary body on the main body by dovetail type fasteners,

[0014] [Fig.2] is a view similar to [Fig.l] showing in more detail a support- head according to one embodiment of the invention,

[0015] [Fig.3] is an unexploded perspective view of the headrest shown in [Fig.2],

[0016] [Fig.4] is a schematic sectional view along a vertical longitudinal plane of the headrest shown in figures 2 and 3,

[0017] [Fig.5] is a schematic sectional view along a horizontal plane of the headrest re presented in figures 2 and 3.

[0018] With reference to the figures, a headrest 1 for a motor vehicle seat is described, said headrest comprising: • a frame 2 for mounting on a back of said seat, • a main body 3, made from molded plastic material, mounted on said frame, • a secondary body 4, made from molded plastic material, slidably mounted in a longitudinal direction X on said main body to be able to adopt a plurality of adjustment positions, said secondary body being integral with a support wall 5 of the head of a passenger, said secondary body being provided with an upper tenon 6a and a lower tenon 6b facing each other along two opposite edges of said secondary body, said tenons each having a connecting end 7 to the rest of said secondary body and a free end 8, said tenons having, in view in said longitudinal direction, a shape falling within a trapezoid having a large base 9 facing inwards and a small base 10 facing outwards, • two upper mortises 11a and lower 11b for receiving, respectively, in sliding of said upper and lower tenons, said mortises being produced by molding said main body,said mortises having a geometry complementary to that of said tenons and opening outwards via their small base 12, so that each tenon 6a, 6b and corresponding mortise 11a, 11b forms a dovetail-type fixing,

[0019] said headrest further comprising a reinforcing crosspiece 13 connecting the free ends 8 of said tenons together so as to stabilize their respective positioning relative to each other.

[0020] According to the embodiment shown, the frame 2 comprises two metal rods 14, in particular tubular, extending vertically.

[0021] As shown, the rods 14 come from a metal tube folded into the general shape of an inverted U, the branches of said U corresponding to said rods, said rods being connected to each other by a middle part 21 of metal tube.

[0022] According to the embodiment shown, the headrest 1 further comprises two upper 15a and lower 15b reinforcing pieces based on molded plastic material, said pieces each being fitted and anchored in a recess 16 provided in a tenon upper 6a and lower 6b respectively.

[0023] According to an embodiment not shown, the reinforcement pieces 15a, 15b are provided with elastically deformable harpoons, so as to be able to deform during their assembly and to return to their nominal configuration once assembled, said harpoons being anchored on stops provided in the recesses 16.

[0024] According to the embodiment shown, the crosspiece 13 is fitted and anchored on each of the reinforcement pieces 15a, 15b.

[0025] According to the embodiment shown, the crosspiece 13 is provided with harpoons 17a, 17b, 17c, said harpoons being elastically deformable so as to be able to deform during their assembly and to return to their nominal configuration once assembled, said harpoons being anchored on stops 18 provided on the reinforcement pieces 15a, 15b.

[0026] According to the embodiment shown, the crosspiece 13 is provided, as illustrated in [Fig.4] • an upper harpoon 17a for blocking upward movement of the upper tenon 6a, • a lower harpoon 17b for blocking downward movement of the lower tenon 6b,

[0027] so that said tenons are locked relative to each other in a vertical direction Z.

[0028] In a manner not shown, the upper 17a and lower 17b harpoons are spaced apart from each other so that the gap between the free ends 8 of the tenons 6a, 6b once the crosspiece 13 is mounted is reduced compared to said gap before mounting of said crosspiece, which makes it possible to improve the robustness of the respective positioning of said tenons between them.

[0029] For example, it may be provided that, once the crosspiece 13 is mounted, the gap between the free ends 8 of the upper 6a and lower 6b tenons is reduced by 3 to 5 mm compared to said gap before mounting of said crosspiece.

[0030] In relation to [Fig.5], the crosspiece 13 is provided with lateral harpoons 17c facing each other, so that the tenons 6a, 6b are blocked relative to each other in a transverse direction (Y).

[0031] The cumulative presence of upper 17a, lower 17b and lateral 17c harpoons makes it possible to ensure very high robustness of the positioning of one tenon 6a relative to the other 6b.

[0032] According to one embodiment, the crosspiece 13 is made from a molded plastic material loaded with reinforcing fibers - in particular glass fibers -, the harpoons 17a, 17b, 17c being produced by molding said crosspiece.

[0033] According to the embodiment illustrated in [Fig.2]: • the headrest 1 further comprises a housing made of molded plastic material

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] comprising a front shell 19 and a rear shell 20 fixed edge to edge against each other, said front shell integrating the support wall 5 for the head of a passenger, • the tenons 6a, 6b come from the molding of said front shell forming the secondary body 4, • the crosspiece 13 is fitted and anchored on said rear shell, so as to reinforce the blocking of the position of one tenon 6a relative to the other 6b. In a manner not shown, the crosspiece 13 may be provided with additional elastically deformable harpoons, so as to be able to deform during their assembly and to return to their nominal configuration once assembled, said harpoons being anchored on additional stops provided on the rear hull 20. As shown in [Fig.5], the mortises 11a, 11b (only the mortise 11a being shown) are provided with at least one spring blade 22 for taking up play, each blade 22 being pressed against the corresponding tenon 6a, 6b (only the tenon 6a being shown). In a manner not shown, the secondary body 4 can be locked by a secondary locking device in the chosen adjustment position. According to an embodiment not shown, the locking device of the secondary body 4 comprises: • a rack secured to said secondary body, said rack extending longitudinally, • a latch mounted to move relative to the main body 3 between a locking position, where it is inserted into a notch of said rack, and an unlocking position, where it is withdrawn from said notch in order to release the sliding of said secondary body. In a manner not shown, it is possible to provide for the main body 3 to be slidably mounted on the frame 2, so that it can be adjusted in height. According to an embodiment not shown, the locking device of the main body 3 may comprise: • at least one notched rod 14 provided with adjustment notches arranged axially, that is to say along the extension axis of said rod, • at least one locking projection mounted to move relative to said main body between a locking position, where said projection is inserted into one of said notches, and an unlocking position, where said projection is withdrawn from said notch in order to release the sliding of said main body.

Claims

Claims

1. Headrest (1) for a motor vehicle seat, said headrest comprising: • a frame (2) for mounting on a back of said seat, • a main body (3), made from molded plastic material, mounted on said frame, • a secondary body (4), made from molded plastic material, slidably mounted in a longitudinal direction (X) on said main body to be able to adopt a plurality of adjustment positions, said secondary body being integral with a support wall (5) for the head of a passenger, said secondary body being provided with an upper tenon (6a) and a lower tenon (6b) facing each other along two opposite edges of said secondary body, said tenons each having a connecting end (7) to the rest of said secondary body and a free end (8),said tenons having, in view along said longitudinal direction, a shape fitting into a trapezium having a large base (9) facing inwards and a small base (10) facing outwards, • two upper (11a) and lower (11b) mortises for receiving said upper and lower tenons in sliding respectively, said mortises being produced by molding said main body, said mortises having a geometry complementary to that of said tenons and opening outwards via their small base (12), so that each tenon (6a, 6b) and corresponding mortise (11a, 11b) forms a dovetail-type attachment, said headrest being characterized in that it further comprises a reinforcing crosspiece (13) connecting together the free ends (8) of said tenons so as to stabilize their respective positioning relative to each other.,

2. Headrest (1) according to claim 1, characterized in that it further comprises two upper (15a) and lower (15b) reinforcing pieces based on molded plastic material, said pieces each being fitted and anchored in a recess (16) provided in a tenon upper (6a) and lower (6b) respectively.

3. Headrest (1) according to claim 2, characterized in that the crosspiece (13) is fitted and anchored on each of the reinforcing pieces (15a, 15b).

4. Headrest (1) according to claim 3, characterized in that the crosspiece (13) is provided with harpoons (17a, 17b, 17c), said harpoons being elastically deformable so as to be able to deform during their assembly and to return to their nominal configuration once assembled, said harpoons being anchored on stops (18) provided on the reinforcing pieces (15a, 15b).

5. Headrest (1) according to claim 4, characterized in that the crosspiece (13) is provided with: • an upper harpoon (17a) for blocking upward movement of the upper tenon (6a), • a lower harpoon (17b) for blocking downward movement of the lower tenon (6b), so that said tenons are blocked relative to each other in a vertical direction (Z).

6. Headrest (1) according to claim 5, characterized in that the upper (17a) and lower (17b) harpoons are spaced apart from each other so that the gap between the free ends (8) of the tenons (6a, 6b) once the crosspiece (13) is mounted is reduced compared to said gap before mounting of said crosspiece.

7. Headrest (1) according to any one of claims 4 to 6, characterized in that the crosspiece (13) is provided with lateral harpoons (17c) facing each other, so that the tenons (6a, 6b) are locked relative to each other in a transverse direction (Y).

8. Headrest (1) according to any one of claims 4 to 7, characterized in that the crosspiece (13) is made from molded plastic material loaded with reinforcing fibers, the harpoons (17a, 17b, 17c) being produced by molding said crosspiece.

9. Headrest (1) according to any one of the preceding claims, characterized in that: • it further comprises a molded plastic material housing comprising a front shell (19) and a rear shell (20) fixed edge to edge against each other, said front shell integrating the support wall (5) of the head of a passenger, the tenons (6a, 6b) come from the molding of said front shell forming the secondary body (4), the crosspiece (13) is fitted and anchored on said rear shell, so as to reinforce the blocking of the position of one tenon (6a) relative to the other (6b).

Images