ERGONOMIC HEADREST FOR A SEAT

Abstract

The invention relates to a headrest (10) for a seat comprising: - a central part (11), and - a movable part (12) between a raised position and a deployed position, - said movable part (12) comprising two lateral head support fins (23), each lateral head support fin (23) being mounted on a corresponding end of a support (24) via an end pivot connection (27) having an end rotation axis (X2), - each end rotation axis (X2) having a substantially vertical orientation when the movable part (12) is in the raised position and a substantially perpendicular orientation relative to the central part (11) when the movable part is in the deployed position, such that each lateral fin (23) is able to rotate about the corresponding end rotation axis (X2) to take a raised position in which the lateral fin (23) is brought closer to a cheek of the passenger. Figure 1b

Description

Title of the invention: ERGONOMIC HEADREST FOR A SEAT

[0001] The present invention relates to an ergonomic headrest for a seat. The invention finds a particularly advantageous, but not exclusive, application with airplane seats intended for economy class. However, the invention may also be implemented with airplane seats intended for business class or with seats in other means of transport, such as, for example, seats installed in motor vehicles, trains, or boats.

[0002] In a manner known per se, a headrest of an economy class airplane seat is mounted on a seat back by means of a headrest structure. The headrest can be movable between a high position and a low position in which the headrest is substantially parallel to the plane of the seat back. Document US2012 / 0139309 teaches the production of a seat headrest comprising a central part and fins mounted on the central part of the headrest by means of pivot connections with a horizontal axis. Each fin is thus movable between a raised position and a deployed position in which the movable part extends substantially perpendicularly relative to the central part and the seat back. The passenger can then rest his head on the upper face of the fins.

[0003] However, such a headrest provides reduced support for the head of the passenger who wishes to sleep comfortably. The passenger may therefore be forced to rest his head on the back of the backrest of the front seat, on the shelf of the same seat, or sometimes on the shoulders of the neighboring passenger, thus constituting a risk of muscular fatigue or respiratory failure.

[0004] The invention aims to effectively remedy this drawback by proposing a headrest for a seat, in particular an airplane seat, comprising:

[0005] - a central part against which a passenger's head can rest, and

[0006] - a movable part mounted on the central part by means of a connection central pivot having a horizontal axis of rotation, said central pivot connection being arranged on a lower edge of the central part, so that the movable part is movable between a raised position and a deployed position in which the movable part extends substantially perpendicularly relative to the central part,

[0007] - said movable part comprises two lateral head support fins, each head support side fin being mounted on a corresponding end of a support via an end pivot connection having an end axis of rotation,

[0008] - each end rotation axis having a substantially vertical orientation when the moving part is in the raised position,

[0009] - each end rotation axis having a substantially perpendicular orientation dicular relative to the central portion when the movable portion is in the deployed position, such that each head support side fin is capable of rotating about the corresponding end rotation axis to assume a raised position in which the head support side fin is brought closer to a cheek of the passenger.

[0010] The invention thus makes it possible, thanks to the presence of the movable part, to offer a large support surface on which the passenger can rest and maintain his head in a comfortable position. When it is in the deployed position, the movable part also has the advantage of being able to be positioned as close as possible to the surface of a cheek of the passenger via the rotation of the fins around the corresponding end rotation axis. The movable part also provides uniformly distributed support on the cheek of the passenger. The movable part also has the advantage of providing neck support for the passenger.

[0011] According to one embodiment of the invention, the movable part has a U shape.

[0012] According to one embodiment of the invention, said headrest is movable between a high position and a low position so that it can accommodate different passenger sizes.

[0013] According to one embodiment of the invention, the movable part extends parallel to the central part when the headrest is in the raised position.

[0014] According to one embodiment of the invention, the central pivot connection is constituted by a rotary friction member to maintain the movable part selectively in the stored position or in the deployed position.

[0015] According to one embodiment of the invention, each end pivot connection is constituted by a hinge having a first portion fixed on one end of the support and a second portion fixed on a corresponding head support fin.

[0016] According to one embodiment of the invention, said headrest comprises a modular interface for attachment to a backrest structure.

[0017] According to one embodiment of the invention, the modular fixing interface comprises two pads each intended to cooperate with a guide rail carried by the backrest structure.

[0018] According to one embodiment of the invention, the modular fixing interface further comprises a clip forming a stop when the headrest is in the previously defined high position.

[0019] According to one embodiment of the invention, said headrest comprises an elastic return member for automatically moving the movable part from the deployed position to the stored position when the passenger's head is not resting on the movable part.

[0020] According to one embodiment of the invention, when the mobile part is in the deployed position, an upper face of a side fin forms a fixed non-zero angle relative to a lower face of said side fin.

[0021] According to one embodiment of the invention, each end pivot connection comprises a device for limiting the angle of rotation of the corresponding lateral fin.

[0022] According to one embodiment of the invention, said headrest comprises a device for retaining the movable part under the action of a strong acceleration undergone by the headrest.

[0023] According to one embodiment of the invention, the retaining device comprises a ball associated with a rod mounted to slide between a default position and an active position in which the rod pushes said ball inside a housing to prevent rotation of the movable part relative to the central part, the passage from the default position to the active position of the rod occurring under the action of the strong acceleration undergone by the headrest.

[0024] According to one embodiment of the invention, an elastic member biases the rod into the rest position when the headrest is not subjected to strong acceleration.

[0025] According to one embodiment of the invention, the retaining device comprises a ball and a part fixed to the movable part of the headrest, said part carrying a pivoting latch capable of rotating under the effect of a movement of the ball generated by the acceleration so as to block the movable part of the headrest.

[0026] According to one embodiment of the invention, the retaining device is provided with a hard point so as to be able to be activated at the start of a downward rotation sequence following a determined angular range in which a force applied to deploy the movable part of the headrest is greater than a force necessary to deploy the movable part over the remainder of a rotation sequence extending from the end of the predetermined angular range to the deployed position.

[0027] The invention also relates to a seat comprising a headrest as previously defined.

[0028] The present invention will be better understood and other characteristics and advantages will become apparent upon reading the detailed description which follows, comprising embodiments given by way of illustration with reference to the appended figures, presented as non-limiting examples, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which:

[0029] [Fig. 1a][Fig. 1b] Figures 1a and 1b are respectively perspective views of the headrest according to the invention when the movable part is in the stored position and in the deployed position;

[0030] [Fig.2] [Fig.2] is a perspective view of the headrest according to the invention without the layers of flexible materials covering its structural parts;

[0031] [Fig.3] [Fig.3] is an exploded perspective view of the headrest according to the present invention;

[0032] [Fig.4a][Fig.4b][Fig.4c] Figures 4a, 4b, 4c are perspective views illustrating different possible configurations of the headrest according to the present invention;

[0033] [Fig.5] [Fig.5] is a perspective view of the rear part of the headrest according to the invention;

[0034] [Fig.6] [Fig.6] is a perspective view of the modular fixing interface disassembled relative to the headrest according to the invention;

[0035] [Fig.7] [Fig.7] is a perspective view illustrating the mounting of the headrest according to the invention on a backrest structure;

[0036] [Fig.8] [Fig.8] is a view showing a passenger having a cheek resting against a fin of the headrest according to the invention in the deployed position;

[0037] [Fig.9] [Fig.9] is a perspective view of the headrest according to the invention illustrating an embodiment in which the fins have a trapezoidal cross-section;

[0038] [Fig. 10a][Fig. 10b] Figures 10a and 10b illustrate a first embodiment of a device for retaining the movable part when the headrest is subjected to strong acceleration;

[0039] [Fig. 11 a][Fig. 11 b] Figures 11 a and 11 b illustrate a second embodiment of a device for retaining the moving part when the headrest is subjected to strong acceleration;

[0040] [Fig. 12a] [Fig. 12b] Figures 12a and 12b illustrate a third embodiment of a device for retaining the movable part when the headrest is subjected to strong acceleration.

[0041] 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.

[0042] The relative terms of the type "horizontal", "vertical", "lower", "upper", are understood by reference to their common meaning when the headrest is in the position of use on a seat.

[0043] By expressions of the type "substantially horizontal" or "substantially vertical" or "substantially perpendicular", we mean the fact that there may be a slight angular offset, less than 20 degrees relative to the direction indicated.

[0044] Figures 1a and 1b show a headrest 10, also called a headrest, for a seat, in particular an airplane seat. The headrest 10 comprises a central part 11 on which a passenger's head can rest, as well as a movable part 12. The central part 11 and the movable part 12 are covered by a layer of flexible material 13, such as for example a layer of foam, itself covered by a cover 15.

[0045] The generally U-shaped movable part 12 is mounted on the central part 11 of the headrest 10 by means of at least one central pivot connection 18 with a horizontal axis XI clearly visible in the figures and in figures 4a, 4b, and 4c. The central pivot connection 18 is arranged on a lower edge of the central part 11. The horizontal axis XI is parallel to the lower edge of the central part 11.

[0046] Thus, the movable part 12 is movable between a raised position in which the movable part 12 extends parallel to the central part 11, preferably in the same plane as the central part 11, and a deployed position in which the movable part 12 extends substantially perpendicular to the central part 11. In the deployed position, the movable part 12 then extends substantially in a horizontal plane.

[0047] In this case, the central pivot connection 18 is constituted by a rotary friction member 19 for holding the movable part 12 selectively in the stored position or in the deployed position. Preferably, the rotary friction member 19 is of the asymmetrical type, that is to say that it requires a greater torque in the direction of deployment than in the direction of retraction towards the raised position.

[0048] The movable part 12 comprises two lateral fins 23 for supporting the head. In this case, the lateral fins 23 are each constituted by a plate of generally trapezoidal shape. Alternatively, the lateral fins 23 may however have a square, rectangular, triangular shape, or any other shape adapted to the application.

[0049] Each lateral fin 23 is mounted on a corresponding end of a support 24 of the movable part 12 by means of an end pivot connection 27 having an end rotation axis X2.

[0050] When the movable part 12 is in the raised position, the end rotation axis X2 has an orientation substantially parallel to a lateral edge of the central part 11. It is thus possible to adapt the angular position of the fin 23 following a lateral rotation around the end rotation axis X2 so as to bring the fin 23 closer to the passenger's cheek, as shown in [Fig.4a]. The lateral deflection angle A1 of a fin around the axis X2 is between 30 and 90 degrees and is preferably of the order of 75 degrees. By "of the order of" is meant a possible variation of 10% around the indicated value.

[0051] When the movable part 12 is in the deployed position, the end rotation axis X2 has an orientation substantially perpendicular to the central part 11. The rotation axis X then extends in a substantially horizontal plane. Each lateral fin 23 is then movable between a default position in which the lateral fin 23 is in the same plane as the movable part 12 and a raised position in which the lateral fin 23 is directed upwards and forms a non-zero angle with respect to a horizontal plane, as shown in [Fig.4c]. The lateral fin 23 can thus be brought closer to the passenger's cheek to improve his comfort. The angle of movement A2 of the lateral fin 23 between the default position and the raised position is for example between 30 and 70 degrees and is preferably of the order of 55 degrees.

[0052] More specifically, as can be seen in Figures 2 and 3, the central part 11 comprises a structural plate 28 on which is mounted a modular fixing interface 30 allowing the fixing of the headrest 10 on a backrest structure 31. The modular fixing interface 30 also visible in Figures 5 and 6 comprises a support plate 33 on which two pads 34 are fixed. These pads 34 are each intended to cooperate with a guide rail 35 carried by the backrest structure 31, as shown in [Fig. 7]. When the seat is in the raised position, the guide rails 35 have a substantially vertical orientation. The headrest 10 is thus movable in translation relative to the backrest structure 31 between a high position and a low position so as to be able to adapt to the different sizes of the passengers.

[0053] Such a configuration has the advantage of having to modify only the configuration of the fixing interface 30, in particular the spacing between the pads 34, so that the headrest 10 can be adapted to different models of seats whose spacing between the rails 35 is likely to vary from one model to another.

[0054] Preferably, the modular fixing interface 30 further comprises a clip 36 forming a stop intended to come to bear against a fixed element of the structure of the seat, for example a pin, when the headrest 10 is in an extremely high position. The clip 36 may have an L shape and is made of a metallic material such that the operator can deform the clip 36 in order to separate the headrest 10 from the backrest structure 31 during a maintenance operation.

[0055] The movable part 12 comprises an elongated support 24 extending longitudinally along the lower edge of the structural plate 28. The elongated support 24 is mounted on the central part 11 by means of the rotary friction member 19. For this purpose, the rotary friction member 19 comprises a body 39 and two end arms 40 movable in rotation relative to the body 39. The end arms 40 may have a non-circular section, in particular a rectangular section.

[0056] Each end arm 40 cooperates with a groove 41 each formed in one end of a central portion 42 in the form of a bridge of the elongated support 24. In order to ensure the mechanical connection between the end arms 40 and the elongated support 24, one or more clamping screws 44 visible in [Fig.2] are each inserted inside through holes made in a wall of the groove 41 and a corresponding end arm 40. Each clamping screw 44 cooperates with a tapped hole made in the elongated support 24. Alternatively, the mechanical connection between the end arms 40 and the elongated support 24 may be ensured by welding, gluing, or force fitting of the end arms 40 inside the corresponding grooves 41.

[0057] Furthermore, the body 39 of the friction member is fixed to a central structural part 49 called the "nose". This nose 49 comprises two parts 50, 51 parallel to each other separated by a spacer 52 inserted inside a notch 53 made in a lower edge of the structural plate 28. The rear part of the nose 49 is fixed to the rear face of the structural plate 28 by screwing, riveting, welding, gluing or any other fixing technique adapted to the application. The body 39 of the rotary member 19 is fixed to a front face of the nose 49 by means of fixing members, such as screws or rivets. Alternatively, the body 39 of the rotary member 19 may be welded or glued to the nose 49. This depends on the application.

[0058] A cover 56 may at least partially cover the nose 49 and a front face of the structural plate 28. This cover 56 has an aesthetic function, insofar as its purpose is to mask the metal structural parts of the headrest 10 when the movable part 12 is in the deployed position.

[0059] Each end of the bridge-shaped central portion 42 is extended by one end of the support 24 on which is mounted an end pivot connection 27. In this case, each end pivot connection 27 is constituted by a hinge 59 having a first portion 61 fixed on the end of the support 24 and a second portion 62 fixed on the lateral fin 23. The two portions 61, 62 are articulated together about the end rotation axis X2. The fixing members used to ensure the fixing between a portion 61, 62 of the hinge 59 and a corresponding element (support 24 or lateral fin 23) may take the form of screws, rivets, or any other fixing member suitable for the application. The hinge 59 may take the form of a friction hinge.

[0060] Each end pivot connection 27 may be provided with a device 65 for limiting the rotation angle of the corresponding lateral fin 23. This device 65 comprises two T-shaped parts, each associated with a portion of the hinge 59 and coming to bear against each other when the lateral fin 23 has reached its limit rotation angle.

[0061] A reinforcing plate 68 may be fixed to a corresponding lateral fin 23. The reinforcing plate 68 may be fixed to a rear face of the lateral fin 23 by screwing, riveting, welding, gluing, or any other fixing technique adapted to the application.

[0062] In the embodiment of [Fig.9], when the movable part 12 is in position deployed, an upper face 70 of a lateral fin 23 may form a fixed non-zero angle A3 relative to a lower face 71 of said lateral fin 23. This makes it possible to limit the angular movement of the lateral fins 23 when the movable part 12 is in the deployed position. The inclination of the upper face 70 relative to the lower face 71 of the lateral fin 23 may be obtained by the layer of flexible material 13 having a trapezoidal cross-section.

[0063] The headrest 10 may include an elastic return member 73 visible in [Fig. 3]. This elastic return member 73 makes it possible to automatically move the movable part 12 from the deployed position to the stored position when the passenger's head is not resting on the movable part 12. The elastic return member 73 may, for example, take the form of a torsion spring integrated inside the central pivot connection 18.

[0064] The operation of the headrest 10 according to the invention installed on a backrest structure 31 is described below. Firstly, the passenger can adapt the vertical position of the headrest 10 by sliding it along the rails carried by the backrest structure 31 in the direction D shown in [Fig.7].

[0065] When the movable part 12 is in a raised position, the passenger can rotate the lateral fins 23 around the end rotation axes X2 then having a vertical orientation. The passenger can thus choose either to leave the lateral fins 23 in the plane of the central part 11, or to bring the lateral fins 23 closer to his cheeks in order to improve the lateral support of his head, as illustrated by [Fig.4a].

[0066] In order to be able to put his head in a comfortable position during a rest phase, the passenger pulls the movable part 12 downwards. The movable part 12 then rotates around the horizontal rotation axis XI to move into the deployed position, as illustrated in Figures 1b and 4b.

[0067] The passenger can then rotate a lateral fin 23 around its end rotation axis X2 so as to move it into a raised position, as illustrated in Figures 4c and 8. The upper face of the lateral fin 23 is then brought closer to the passenger's cheek to improve his comfort.

[0068] Alternatively, all the pivot connections may have the same configuration, i.e. either all the pivot connections may take the form of friction hinges 59 or friction rotating members 19.

[0069] Advantageously, as illustrated by figures 10 to 12, the headrest 10 comprises a device 75 for retaining the movable part 12 under the action of a strong acceleration undergone by the headrest 10. This retaining device 75 makes it possible in particular to avoid an uncontrolled movement of the movable part 12 of the headrest 10 during an impact suffered by the aircraft.

[0070] In the embodiment of figures 10a and 10b, the retaining device 75 comprises a ball 76 associated with a rod 77 mounted to slide relative to a fixed support 78 mounted on the movable part 12 between a default position and an active position in which the rod 77 pushes said ball 76 inside a housing 79 provided in the central part 11 to prevent rotation of the movable part 12 relative to the central part 11, the passage from the default position to the active position of the rod 77 occurring under the action of the strong acceleration undergone by the headrest 10.

[0071] For this purpose, the rod 77 comprises a small diameter section 77.1 arranged opposite the ball 76 when the rod 77 is in the default position, so that the ball 76 is released from the housing made in one of the parts among the fixed central part 11 or the movable part 12 of the headrest 10. The rod 77 comprises a large diameter section 77.2 intended to apply a radial force on the ball 76 so as to push it inside the housing, when the rod 77 is in the active position. The rod 77 is oriented in the direction of the acceleration undergone by the headrest 10.

[0072] An elastic member 80, such as a spring arm, biases the rod 77 into the rest position when the headrest 10 is not subjected to strong acceleration. This elastic member 80 makes it possible to define the resistance force from which the rod 77 passes from the rest position to the active position.

[0073] Alternatively, the structure may be reversed, i.e. the fixed support 78 may be mounted on the central part 11 while the housing 79 intended to receive the ball 76 is provided in the mobile part 12.

[0074] In the embodiment of Figures 11a and 11b, the retaining device 75 comprises a ball 82 and a support part 83 fixed on the movable part 12 of the headrest 10. The part 83 carries a pivoting latch 84 capable of rotating under the effect of a movement of the ball 82 generated by the acceleration so as to block the movable part 12 of the headrest 10. For this purpose, one end of the latch 84 may be housed inside a housing 85 made in the central part 11 of the headrest 10. In order to ensure the rotation of the latch 84, the ball 82 may roll against an inclined face 86 formed in the part 83 or the latch 84.

[0075] The ball 82 is thus movable between a rest position in which the ball 82 is located on the side of the lowest level of the inclined face 86, so that the latch 84 is released from the housing 85 and an active position in which the ball 82 is located on the side of the highest level of the inclined face 86, so that the latch 84 cooperates with the housing 85 formed in the central part 11.

[0076] Alternatively, the structure could be reversed, that is to say that the support part 83 could be mounted on the central part 11 while the housing 85 intended to receive the latch 84 is provided in the movable part 12.

[0077] Thus, in the first two embodiments, the retaining device 75 comprises a movable element (the rod 77 or the ball 82) capable of moving, under the action of strong acceleration, towards an active position making it possible to ensure blocking of the movable part 12 relative to the central part 11.

[0078] In the embodiment of Figures 12a and 12b, the retaining device 75 is provided with a hard point 84 so as to be able to be activated at the start of a downward rotation sequence following a determined angular range in which a force applied to deploy the movable part 12 of the headrest 10 is greater than the force necessary to deploy the movable part 12 over the remainder of a rotation sequence extending from the end of the predetermined angular range to the deployed position.

[0079] For this purpose, the retaining device 75 comprises an arm 88 movable in rotation relative to the movable part 12 and an elastic member 89, such as a spring, urging the arm 88 against the hard point 84 produced on the central part 11. In this case, the hard point 87 is constituted by a rounded slope. To move the movable part 12 into the deployed position, it is necessary to compress at least partially the spring 89 so that the arm 88 can pass the obstacle constituted by the rounded slope. The fact of having to compress the spring 89 increases the force to be applied to deploy the movable part 12 over the determined angular range. The value of this angular range can be adapted according to the shape and extent of the rounded slope.

[0080] Of course, the various features, variants and / or embodiments of the present invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

[0081] Furthermore, 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 may be envisaged by those skilled in the art within the scope of the present invention and in particular all combinations of the different operating modes described above, which may be taken separately or in association.

Claims

Claims

1. Headrest (10) for a seat, in particular an airplane seat, comprising: - a central part (11) against which the head of a passenger can rest, said central part comprising a structural plate (28), and - a movable part (12) mounted on the central part (11) by means of a central pivot connection (18) having a horizontal axis of rotation (XI), said central pivot connection (18) being arranged on a lower edge of the central part (11), so that the movable part (12) is movable between a raised position and a deployed position in which the movable part (12) extends substantially perpendicularly to the central part (11), characterized in that said movable part (12) comprises: - an elongated support (24) extending longitudinally along a lower edge of the structural plate (28),said elongated support (24) being mounted on the central part (11) by means of a rotary friction member (19) constituting the central pivot connection (18), and - two lateral head support fins (23), each lateral head support fin (23) being mounted on a corresponding end of the support (24) by means of an end pivot connection (27) having an end rotation axis (X2), - each end rotation axis (X2) having a substantially vertical orientation when the movable part (12) is in the raised position, - each end rotation axis (X2) having a substantially perpendicular orientation relative to the central part (11) when the movable part (12) is in the deployed position,such that each head support side fin (23) is able to rotate about the corresponding end rotation axis (X2) to take a raised position in which the head support side fin (23) is brought closer to a cheek of the passenger.,

2. Headrest according to claim 1, characterized in that the movable part (12) has a U shape.

3. Headrest according to claim 1 or 2, characterized in that it is movable between a high position and a low position so as to be able to adapt to different sizes of passengers.

4. Headrest according to any one of claims 1 to 3, characterized in that the movable part (12) extends parallel to the central part (11) when the headrest (10) is in the raised position.

5. Headrest according to any one of claims 1 to 4, characterized in that the central pivot connection (18) is constituted by a rotary friction member (19) to hold the movable part (12) selectively in the stored position or in the deployed position.

6. Headrest according to any one of claims 1 to 5, characterized in that each end pivot connection (27) is constituted by a hinge (59) having a first portion (61) fixed on one end of the support (24) and a second portion (62) fixed on a corresponding head support fin (23).

7. Headrest according to any one of claims 1 to 6, characterized in that it comprises a modular fixing interface (30) on a backrest structure (31).

8. Headrest according to claim 7, characterized in that the modular fixing interface (30) comprises two pads (34) each intended to cooperate with a guide rail (35) carried by the backrest structure (31).

9. Headrest according to any one of claims 1 to 8, characterized in that it comprises an elastic return member (73) to automatically move the movable part (12) from the deployed position to the stored position when the passenger's head is not resting on the movable part (12).

10. Headrest according to any one of claims 1 to 9, characterized in that when the movable part (12) is in the deployed position, an upper face (70) of a lateral fin (23) forms a fixed non-zero angle relative to a lower face (71) of said lateral fin (23).

11. Headrest according to any one of claims 1 to 10, characterized in that it comprises a device (75) for retaining the movable part (12) under the action of a strong acceleration undergone by the headrest (10).

12. Headrest according to claim 11, characterized in that the retaining device (75) comprises a ball (76) associated with a rod (77) mounted to slide between a default position and an active position in which the rod (77) pushes said ball (76) inside a housing to lock the movable part (12) in rotation relative to the central part (11), the passage from the default position to the active position of the rod (77) occurring under the action of the strong acceleration undergone by the headrest (10).

13. Headrest according to claim 11, characterized in that the retaining device (75) comprises a ball (82) and a part (83) fixed on the movable part (12) of the headrest (10), said part (83) carrying a pivoting latch (84) capable of rotating under the effect of a movement of the ball (82) generated by the acceleration so as to block the movable part (12) of the headrest (10).

14. Headrest according to claim 11, characterized in that the retaining device (75) is provided with a hard point (84) so ​​as to be able to be activated at the start of a downward rotation sequence following a determined angular range in which a force applied to deploy the movable part (12) of the headrest (10) is greater than a force necessary to deploy the movable part (12) over the remainder of a rotation sequence extending from the end of the predetermined angular range to the deployed position.

15. A seat comprising a headrest (10) as defined in any one of the preceding claims.

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