Headrest system for a motor vehicle seat back

Abstract

The invention relates to a headrest system (1) for a motor vehicle seat backrest, comprising a support (3) mounted on a base (5) by means of a longitudinal adjustment device comprising a rear connecting rod (6) and a front connecting rod (9) secured to said support by means of an additional front connecting rod (12) articulated at its ends respectively to said front connecting rod along a fourth transverse axis (11) and to said support along a fifth transverse axis (13) which is slidably mounted in a guide (14) formed in said base, said system further comprising a first locking means for said fifth axis in said guide in a plurality of positions and a means for unlocking said first locking means (15), said first locking means being returned to the locked position by a first spring means. Figure 1a

Description

Title of the invention: Headrest system for a motor vehicle seat back

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

[0002] It is known, in particular from document EP-3 372 445, to produce a headrest system for a motor vehicle seat backrest, said system comprising: • a headrest comprising a cushion to support the head of an occupant of said seat and a support receiving said cushion from the front, • a base intended to be fixed over the top of said backrest, said base being positioned behind said support,

[0003] said support being mounted on said base by means of a longitudinal adjustment device for said support, said device comprising: • a rear connecting rod articulated at its ends respectively to said base along a first transverse axis and to said support along a second transverse axis, • and a front connecting rod articulated at its ends respectively to said base along a third transverse axis and securely attached to said support along a fourth transverse axis.

[0004] However, such an arrangement does not allow the support's attitude to be maintained - that is to say its inclination when viewed from a transverse direction - or at least to control said attitude in a controlled manner, which may cause discomfort for a seat occupant adjusting said support from one adjustment position to another.

[0005] Furthermore, in the known embodiment, the support is locked in the chosen adjustment position by a locking means located in the lower part of the front connecting rod; this results in a very significant lever arm effect in the event of an impact on the headrest, which requires the implementation of connecting rods and a locking means of very high robustness - and therefore of significant weight and bulk - so that the support remains in its adjustment position.

[0006] The invention aims to overcome these drawbacks.

[0007] To this end, the invention proposes a headrest system for a motor vehicle seat backrest, said system comprising: • a headrest comprising a cushion to support the head of an occupant of said seat and a support receiving said cushion from the front, • a base intended to be fixed over the top of said backrest, said base being positioned behind said support,

[0008] said support being mounted on said base by means of a longitudinal adjustment device for said support, said device comprising: • a rear connecting rod articulated at its ends respectively to said base along a first transverse axis and to said support along a second transverse axis, • and a front connecting rod articulated at its ends respectively to said base along a third transverse axis and securely attached to said support,

[0009] said system further having the following characteristics: • said front connecting rod is secured to said support by means of an additional front connecting rod articulated at its ends respectively to said front connecting rod along a fourth transverse axis and to said support along a fifth transverse axis, • said fifth axis is mounted to slide in a guide provided in said base, said fifth axis sliding from one end to the other of said guide when said support is actuation between maximum rear and maximum front adjustment positions, so as to define the attitude of said support in any adjustment position, • it further comprises a first means for locking said fifth axis in said guide in a plurality of positions, so as to lock said support in the chosen adjustment position, • it further includes an actuation means for unlocking said first locking means, said first locking means being returned to the locked configuration by a first spring means.

[0010] In this description, the terms of positioning in space (longitudinal, transverse, vertical, lateral, front, rear, ...) are taken with reference to the vehicle in which the headrest system is located, said vehicle extending longitudinally along its length (X axis), transversely along its width (Y axis) and vertically along its height (Z axis).

[0011] With the proposed arrangement, it is possible to maintain the position of the support during its adjustment, or at least to control it according to a controlled evolution, which makes it possible to optimize the comfort for a seat occupant adjusting said support from one adjustment position to another.

[0012] In addition, the support is held in its adjustment position in the event of an impact by the guide - made in particular of metal - and the first locking means, located at the level of the fifth axis, which does not involve the lever arm observed in the prior art embodiment; this results in the possibility of using connecting rods of moderate resistance allowing for a lighter and more compact headrest.

[0013] Other features and advantages of the invention will become apparent from the following description, made with reference to the accompanying figures, in which:

[0014] [Fig-1] is a schematic side view of a system according to one embodiment, the support being in maximum rear position ([Fig. la]) and maximum front position ([Fig.lb]),

[0015] [Fig.2] is a partial schematic perspective view of the system shown in [Fig.l],

[0016] [Fig.3] is analogous to [Fig.2], with certain elements of the system not shown.

[0017] [Fig.4a] and

[0018] [Fig.4b] are partial schematic perspective views of the system presented in the previous figures, the first locking method being activated ([Fig.4a]) and deactivated ([Fig.4b]),

[0019] [Fig.5] is a partial schematic longitudinal vertical section view of the system shown in the previous figures, the second locking method being activated.

[0020] With reference to the figures, a headrest system 1 for a motor vehicle seat back is described, said system comprising: • a headrest comprising a cushion 2 for supporting the head of an occupant of said seat and a support 3 - in particular made of molded plastic material - receiving said cushion from the front, • a base 5 intended to be fixed over the top of said backrest, said base being positioned behind said support,

[0021] said support being mounted on said base by means of a longitudinal adjustment device for said support, said device comprising: • a rear connecting rod 6 articulated at its ends respectively to said base along a first transverse axis 7 and to said support along a second transverse axis 8, • and a front connecting rod 9 articulated at its ends respectively to said base along a third transverse axis 10 and securely attached to said support,

[0022] said system further having the following characteristics: • said front connecting rod is secured to said support by means of an additional front connecting rod 12 articulated at its ends respectively to said front connecting rod along a fourth transverse axis 11 and to said support along a fifth transverse axis 13, • said fifth axis is mounted to slide in a guide 14 provided in said base, said fifth axis sliding from one end to the other of said guide when said support is actuation between maximum rearward and maximum forward adjustment positions, so as to define the attitude of said support in any adjustment position, • it further comprises a first means for locking said fifth axis in said guide in a plurality of positions, so as to lock said support in the chosen adjustment position, • it further includes an unlocking actuation means 15 - here in the form of a rotating pallet - of said first locking means, said first locking means being returned to the locking configuration by a first spring means, not shown.

[0023] According to the embodiment shown, the guide 14 comprises two lights 16 arranged symmetrically laterally on either side of a longitudinal vertical plane of symmetry P of the adjustment device, each of said lights receiving by sliding a respective end of the fifth axis 13.

[0024] In particular, the lights 16 are provided in metal plates, so as to ensure robust retention of the support 3 in its adjustment position in case of shock.

[0025] According to the embodiment shown: • the first locking means comprises a locking piece 17 having two racks 18 arranged laterally on either side of the plane of symmetry P, • said part is mounted for rotation about a sixth axis 19 transverse behind the support 3,

[0026] the unlocking actuation means 15 being mounted in interaction with said part so as to allow the actuation of said part between: • an angular locking position where said racks receive the ends of the fifth axis 13 in two respective locking notches 20 in the chosen longitudinal adjustment position, said part being returned to said position by the first spring means, • and an angular unlocking position where said ends disengage from said notches to allow adjustment of the support 3 into another position.

[0027] According to the embodiment shown, the unlocking actuation means 15 is mounted to interact with the locking piece 17 via a rotating intermediate piece 21 having a first cam surface 22 interacting with said actuation means and a second cam surface 23 interacting with said locking piece.

[0028] According to the embodiment shown, the lights 16 are arc-shaped, said shape being arranged so as to maintain the plate of the support 3 in all its longitudinal adjustment positions.

[0029] According to an unrepresented variant, lights 16 can be provided with a shape arranged so as to progressively change the shape of the support 3.

[0030] According to the embodiment shown, the connecting rods 6, 9, 12 are in the form of stamped metal plates - so as to present the expected rigidity - fitting inside the base 5 in a transverse direction.

[0031] According to the embodiment shown, system 1 further comprises: • a plate 24 - in particular made of molded plastic material - mounted to slide vertically - here by rails not visible in the figures - at the front of the support 3 so as to be height adjustable, the cushion 2 being mounted over the said plate so that the said support receives the said cushion via the said plate, • a second means for locking said plate in the chosen height adjustment position, said second means being returned to the locked position by a second spring means 28 - said second spring means possibly being combined with the first spring means -,

[0032] the unlocking actuation means 15 being arranged to simultaneously unlock said second locking means and the first locking means.

[0033] According to the embodiment shown, the second locking means comprises a latch 25 movablely mounted on the support 3 between a locking position and an unlocking position, said latch cooperating with a secondary rack 26 provided on the rear face of the plate 24 so as to define a plurality of vertical adjustment positions depending on the insertion of said latch into one or the other of the notches of said rack.

[0034] According to the embodiment shown, the latch 25 in the locking position is blocked by a projection 27 provided on the locking piece 17, said projection retracting to unlock said latch when the unlocking actuation means 15 is activated, this so as to reinforce the locking of the plate 24 in its height adjustment position.

Claims

1. Demands (1) Headrest system for a motor vehicle seat backrest, said system comprising: • a headrest comprising a headrest cushion (2) for the head of an occupant of said seat and a support (3) receiving said cushion from the front, • a base (5) intended to be fixed over the top of said backrest, said base being positioned behind said support, said support being mounted on said base by means of a longitudinal adjustment device for said support, said device comprising: • a rear connecting rod (6) articulated at its ends respectively to said base along a first transverse axis (7) and to said support along a second transverse axis (8), • and a front connecting rod (9) articulated at its ends respectively to said base along a third transverse axis (10) and securely attached to said support, said system being characterized in that: • said front connecting rod is secured to said support by means of an additional front connecting rod (12) articulated at its ends respectively to said front connecting rod along a fourth transverse axis (11) and to said support along a fifth transverse axis (13), • said fifth axis is mounted to slide in a guide (14) provided in said base, said fifth axis sliding from one end to the other of said guide when said support is actuation between maximum rearward and maximum forward adjustment positions, so as to define the attitude of said support in any adjustment position, • it further comprises a first means for locking said fifth axis in said guide in a plurality of positions, so as to lock said support in the chosen adjustment position, • it further includes an actuation means for unlocking (15) said first locking means, said first locking means being returned to the locked configuration by a first spring means.

2. System according to claim 1, characterized in that the guide (14) comprises two lights (16) arranged symmetrically laterally on either side of a longitudinal vertical plane of symmetry (P) of the adjustment device, each of said lights receiving by sliding a respective end of the fifth axis (13).

3. System according to the preceding claim, characterized in that: • the first locking means comprises a locking piece (17) having two racks (18) arranged laterally on either side of the plane of symmetry (P), • said piece is mounted for rotation about a sixth transverse axis (19) behind the support, the unlocking actuation means (15) being mounted in interaction with said piece so as to allow the actuation of said piece between: • an angular locking position where said racks receive the ends of the fifth axis (13) in two respective locking notches (20) in the selected longitudinal adjustment position, said piece being returned to said position by the first spring means, • and an angular unlocking position where said ends disengage from said notches to allow the adjustment of the support (3) in another position.

4. System according to the preceding claim, characterized in that the unlocking actuation means (15) is mounted to interact with the locking piece (17) via a rotating intermediate piece (21) having a first cam surface (22) interacting with said actuation means and a second cam surface (23) interacting with said locking piece.

5. System according to any one of claims 2 to 4, characterized in that the lights (16) are arc-shaped, said shape being arranged so as to maintain the support (3) in all its longitudinal adjustment positions or to make it evolve progressively.

6. System according to any one of the preceding claims, characterized in that the connecting rods (6,9,12) are in the form of stamped metal plates that fit inside the base (5) in a transverse direction.

7. A system according to any one of the preceding claims, characterized in that it further comprises: • a plate (24) mounted to slide vertically at the front of the support (3) so as to be height adjustable, the cushion (2) being mounted over the said plate so that the support receives the cushion via the said plate, • a second means for locking the said plate in the chosen height adjustment position, the second means being returned to the locked position by a second spring means (28), the unlocking actuation means (15) being arranged to simultaneously unlock the second locking means and the first locking means.

8. System according to the preceding claim, characterized in that the second locking means comprises a latch (25) movably mounted on the support (3) between a locking position and an unlocking position, said latch cooperating with a secondary rack (26) provided on the rear face of the plate (24) so ​​as to define a plurality of vertical adjustment positions depending on the insertion of said latch into one or the other of the notches of said rack.

9. System according to the preceding claim, characterized in that the latch (25) placed in the locking position is blocked in said position by a projection (27) provided on the locking piece (17), said projection retracting to unlock said latch when the unlocking actuating means (15) is activated.

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