Adjustable headrest for motor vehicle seat

An adjustable headrest for motor vehicle seat. The headrest includes a support structure fixed to a backrest and a body having a front shell and a rear shell. The front shell has a front face intended for contact with the head of a user of the seat, the front face being movable relative to the support structure along a front-rear direction denoted X, over a total travel distance. The total travel distance is formed by a first travel portion provided by a mounting enabling translational movement of the body relative to the support structure while maintaining the position of the front shell relative to the rear shell substantially constant. The total travel distance is also formed by a second travel portion provided by a mounting enabling translational movement of the front shell alone relative to the rear shell.

TECHNICAL FIELD

The present invention relates to headrests for motor vehicle seats.

In particular, the invention relates primarily to a headrest where the position of its front face is adjustable in the longitudinal direction (denoted X) (close to the vehicle longitudinal direction) and optionally adjustable in the substantially vertical direction (denoted Z).

BACKGROUND

When using a single-volume (“one-piece”) headrest, the adjustment travel along X is rather limited by the compatibility of the internal mechanism and the support structure, and by the style constraints imposed on headrests.

In order to increase the adjustment travel along X, the trend is toward a “dual-volume” solution where the front cushion of the headrest can be moved relative to a base structure in the central and rear area of the headrest.

Such a headrest is known from patent document FR2979867 originating from the Applicant. Another solution is disclosed in US Patent Application Publication No. 2010/0127541. In both cases, the position of the rear part of the headrest is unchanged and the thickness along the longitudinal direction (X) increases when bringing the front face closer to the user's head. However, the thicker the headrest in the longitudinal direction, the more the aesthetic appearance of the headrest is degraded and the more the visibility of the other occupants of the vehicle is affected, in some cases including the driver (field of vision partially obscured by the passenger headrest).

Another concern is related to safety in the event of an impact: this requires positive locking of the front face to prevent rearward travel, in order to protect the neck of the seat occupant in case of impact. In this context, known solutions such as those involving continuous deformation with an upper hinge region are not ideal.

There therefore remains a need to provide a headrest allowing wide adjustment in the longitudinal direction X, while limiting its volume (and therefore the obstruction of the view) and while maintaining compliance with load resistance specifications.

SUMMARY

To this end, the invention proposes, in at least one embodiment, an adjustable headrest for a motor vehicle seat, comprising:a support structure intended to be fixed to a backrest of said seat,a body connected to the support structure, comprising at least:a front shell having a front face intended for contact with the head of a user of the seat,a rear shell which forms, in complementarity with the front shell, a casing of the headrest body,the front face being movable relative to the support structure along a front-rear direction denoted X, over a total travel distance, this total travel distance being formed by at least:a first travel portion provided by a mounting enabling translational movement of the body relative to the support structure, the position of the front shell relative to the rear shell remaining substantially constant,a second travel portion provided by a mounting enabling translational movement of the front shell alone relative to the rear shell.

In other words, during the first travel portion, the total thickness of the headrest along X does not change, whereas during the second travel portion only, the total thickness of the headrest along X increases.

With these arrangements, the thickness of the body of the headrest remains constant and moderate for the first travel portion and the headrest has an attractive aesthetic appearance and a narrow profile which facilitates visibility while allowing additional travel when necessary.

In preferred embodiments of the invention, one or more of the following arrangements may possibly be used.

Advantageously, the total travel distance (CT) is at least equal to 50 mm; quite ample travel is thus obtained that is suitable for all morphologies and preferences of the occupants.

According to one embodiment, the first and second travel portions (C1, C2) each have a length that is close to half that of the total travel distance, whereby the total travel distance comprises two balanced portions, the first travel portion and the second travel portion, for example each having a travel distance of at least 25 mm.

Optionally, guiding is provided by guide elements which may be arranged concentrically with spatial overlap, each guide being effective for a length of at least 30 mm, preferably about 40 mm.

According to one embodiment, the headrest comprises a guide plate mounted on the support structure, preferably with a vertical sliding movement, the rear shell and the front shell being directly or indirectly connected to this guide plate; in addition, in an optional feature, the height position of the headrest is adjustable by sliding the guide plate vertically.

According to one embodiment, the rear shell is mounted so as to slide (along X) on the guide plate, forming the first travel portion, and the front shell is mounted so as to slide (along X) on the rear shell, forming the second travel portion. This proves to be a particularly simple and compact assembly.

According to one embodiment, the following guide elements are provided:two first guide sleeves31,32, securely fixed to the guide plate,two second sleeves41,42, securely fixed to the rear shell and slidably mounted in the first sleeves,two rods51,52rigidly fixed to the front shell and slidably mounted in the second sleeves; this proves to be a particularly compact assembly, thus advantageously obtaining a coaxial, concentric, robust, and compact assembly.

According to one embodiment, there may further be provided elements for locking the position of the headrest, in particular the front shell, and a control device for unlocking the locking elements to enable changing the adjustment position. This allows a simple method for adjusting the position of the headrest along X.

According to one embodiment, it is also possible to provide at least one return spring for biasing the front shell rearward in the absence of external forces and when not locked, whereby the headrest returns naturally to the rearmost position when the control button is actuated and without any particular action by the user.

According to one embodiment, the support structure comprises two headrest uprights extended by headrest pins, extending in a direction substantially corresponding to the vertical when the seat is in the normal position of use, and a cross-member on which the guide plate is mounted, possibly slidably; this is a very mechanically robust assembly, which allows compliance with safety specifications and requirements.

According to one embodiment, advantageously the longitudinal thickness of the headrest body remains less than 95 mm along the first travel portion; there is thus a relatively narrow profile which facilitates a good field of view for the occupants of the vehicle and in particular the driver.

The present invention also relates to a seat comprising a headrest as described above.

Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings.

DETAILED DESCRIPTION

In the various figures, the same references designate identical or similar elements.

FIG. 1shows a seat104of a motor vehicle, having a seating portion intended for receiving an occupant101of the seat and a backrest103supporting a headrest10by means of two parallel pins1a,1bextending along a longitudinal axis of the pins. The pins extend in a direction at or near a first direction Z in the present application, relatively close to the vertical in the normal position of use of the seat.

The seat in question may be the driver seat or the front passenger seat; it is not excluded to apply this invention to the rear seats or to the seats of trucks, vans, utility vehicles, or off-road vehicles.

In the example illustrated, the pins1a,1bare inserted without play into two sheaths (not shown) of the backrest103in a relatively conventional manner, said pins being extended by uprights11,12, extending upwards along direction Z, which are connected by an upper connecting part13also called a cross-member. This forms the support structure1of the headrest in the sense of the invention.

Advantageously, the headrest with its pins can be removed from the backrest in a manner known per se, and subsequently reinstalled in a manner also known per se.

As will be explained in greater detail below, in the example presented here the headrest10is adjustable in what is referred to as the longitudinal direction, denoted X, substantially corresponding to the front-rear direction when the seat is in the normal position of use. More precisely, it is the front face70of the headrest that is adjustable to be more or less advanced with respect to the head102of the seat occupant101.

Adjustment may also be provided in the vertical direction, meaning in the direction denoted Z. In the example illustrated, it is the entire body of the headrest that can be moved vertically.

As illustrated inFIGS. 2 to 6, the headrest comprises, in addition to the support structure1already mentioned:a guide plate2mounted so as to slide on the support structure1in the vertical direction Z,a body8connected to the support structure via the guide plate, said body comprising a front shell7with a front face70intended for contact with the head102of a user101of the seat, and a rear shell6which forms, in complementarity with the front shell7, a casing80of the headrest body,locking elements4and a control device9, these locking elements making it possible to immobilize the front shell7with respect to the guide plate in the longitudinal direction X and to immobilize the guide plate2with respect to the support structure1in the vertical direction Z.

It should be noted that the front shell7is generally covered with padding and/or a covering (not shown here for reasons of clarity). The same applies to the rear shell6which may be covered with a covering (not shown).

The front shell7and the rear shell6are made of lightweight but relatively rigid synthetic material.

The uprights11,12extended by the pins1a,1bare formed by metal tubes, preferably with a slight bend just below the headrest body. The cross-member13is made either of overmolded metal or of a synthetic material reinforced with fibers and connected to the uprights by overmolding, or of solid molded plastic with reinforcing ribs.

The guide plate2may be made of metal, for example by a process of folding and cutting a metal blank; it is not excluded to create the plate of robust plastic.

More precisely, concerning the kinematics and the assembly of the various elements, we have:the guide plate2which is mounted to allow translational movement along Z relative to the support structure,two first guide sleeves31,32securely fixed to the guide plate2,two second sleeves41,42(which may also be called intermediate sliders) securely fixed to the rear shell and slidably mounted in the first sleeves31,32,two rods51,52rigidly fixed to the front shell and slidably mounted in the second sleeves41,42.

Advantageously, the assembly on the left, meaning the assembly that includes first sleeve31, second sleeve41, and rod51, is concentric to axis X1.

Similarly, the assembly on the right, namely the assembly that includes sleeve32, second sleeve42, and rod52, is similarly mounted in a coaxial arrangement along the axis denoted X2.

Each of the rods51,52(also called small struts) is formed by a hollow cylindrical tube in the example illustrated, made of metal or plastic. Each of the rods51,52each comprises a front cap screw37at its front end57and a rear cap screw36at its back end58; these cap screws are screwed into an internal thread of the tube (FIGS. 5A, 5B, 5C).

Each of the second sleeves41,42forms a right circular cylinder with a rear base46connected to the rear shell, a rear tubular portion49, and, as an extension, a front tubular portion48which terminates in a front end45. The front tubular portion48has an inside diameter which is very slightly greater than the outside diameter of the rod51so as to provide the linear guiding function for at least 30 mm of length, preferably at least 40 mm of length.

Each of the first sleeves31,32forms a right circular cylinder with a rear tubular portion39and, as an extension, a front tubular portion38which terminates in a front end30. Front tubular portion38has an inside diameter which is very slightly greater than the outside diameter of front tubular portion48so as to provide a linear guiding function. Rear tubular portion39has an inside diameter which is very slightly greater than the outside diameter of the aforementioned rear tubular portion49, which completes the linear guiding function.

Between the first and second sleeves, guidance is provided for at least 30 mm in length, preferably at least 40 mm in length.

With such an assembly, the slidable mounting of the rear shell on the guide plate provides a first adjustment travel portion denoted C1(seeFIG. 5A); and the slidable mounting of the front shell7on the rear shell6provides a second adjustment travel portion denoted C2(seeFIG. 5B).

The sum of the two travel portions C1, C2forms a total travel distance denoted CT which is available for adjusting the front face along X, the length of this total travel distance CT being at least equal to 50 mm, preferably about 60 mm. Each of the two travel portions C1, C2is preferably at least 25 mm each.

When the user actuates the control device9to unlock the current position starting from the rearmost position, it is the first travel portion C1that is first available and biased, namely the simultaneous movement of the front and rear shell ensemble relative to the guide plate. This first translational movement reaches a stop when the external shoulder44of the second sleeve41abuts against the internal shoulder34of the first31. If the forward traction of the front shell7is continued, then the second travel portion C2is engaged, where the rear shell remains stationary and the front shell moves away from the rear shell. The second travel portion ends when the rear cap screw36abuts against the inner shoulder43of the second sleeve41.

To contribute to this kinematic arrangement, at least one return spring81is provided to bias the front shell7rearward in the absence of external forces and when not locked. This return spring will be compressed in the second travel portion C2(FIG. 4C, 5C) but is not subjected to stresses in the first travel portion C1(FIG. 4A, 5A, 5A, 5B). In the example shown, there is a spring8on the left arranged around rod51and another spring82on the left arranged around rod52.

Each spring comprises a front end87bearing on a shoulder47of the second sleeve and a back end88bearing on a shoulder of the rear cap screw36.

The return springs81,82are typically of the very common metal spiral compression type. The stiffness is chosen to allow displacement (compression) under moderate effort by the user, along the second travel portion C2.

The guide plate2comprises two uprights21,22each having a U-shaped profile with the opening facing one another, the two uprights being connected to one another by a rear face23and a front face24. On the front face24, there is a rib-shaped projection extending vertically and forwardly with a notch25used for preventing movement along direction Z. There is also a central recess29on the front face24, intended for preventing movement along direction X.

In the absence of any action requested by the control device9, the current position is locked, more particularly the front shell7is made rigid with a toothed piece84which engages with one or more notches28available in the guide plate, more precisely on the edge of the abovementioned central recess29.

Such locking makes it possible to avoid rearward movement of the front face70in the event of an impact, providing good protection for the neck of the occupant101.

The control device9comprises an easily actuated button91and a guide90, and comprises a return element99and a control carriage40which releases the locking elements, in the current case the locking elements for direction Z (wire92) and the locking elements for direction X (toothed piece84).

The control carriage40is mounted so as to be slidable along Y (transverse direction) relative to the front shell and thus selectively moveable when the button is pressed against the action of the spring86.

A notched bar84comprises a plurality of successive notches89along X, into which a tooth (more generally a projection)28integral with the plate2is inserted. The notched bar is returned to the locking position by two springs98, independently of the return of the control carriage.

Adjustment of the position of the front face70of the front shell7will typically be done by pressing the actuation button91and pulling the front shell forward, typically with one or both hands of the user101seated on the seat.

Sliding of the support plate2along the first direction Z may be prevented by first catching means14, which in the illustrated example are notches on the uprights. A wire92inserted into a guide casing93engages with the notches14, preventing any sliding along Z.

When the user presses the button91, this moves the control carriage inwardly, forcing the wire92away from the notches14, which unlocks the sliding along Z.

It will be noted that in the first travel portion C1, the thickness of the headrest body denoted EX inFIG. 4Ais advantageously less than 100 mm and in the illustrated example less than 95 mm.

As for the guidance, it is possible in an alternative solution to have the front shell slidably mounted on the guide plate, similarly to the rear shell, with a return of one toward the other. The travel of the rear shell is shorter than that of the front shell, which makes it possible to have first C1and second C2travel portions as described above.

The locking elements could be arranged differently.

Although the example illustrated shows travel portions C1and C2of substantially the same length, it is possible to envisage C1and C2being different travel distances, by changing the abutment of the rear shell for example.