Headrest for motor vehicle seat

A headrest for a motor vehicle seat comprises at least one spindle for assembling the headrest in a backrest of the seat; and a body provided with at least one housing in the shape of a sleeve for receiving one end of said spindle, the spindle comprising, in an upper portion, a shoulder capable of cooperating with a horizontal rib, protruding inside of a housing of the body, to lock any translation of the spindle in its housing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to motor vehicle seats and, more specifically, to the forming of a headrest for such seats.

2. Discussion of Prior Art

Different types of headrests for motor vehicle seats are known. Two types of headrests can be mentioned, those integrating an adjustment mechanism and simpler ones for which the position of a body of the headrest with respect to spindles engaged in the backrest of the seat is fixed. In the first category, the spindles generally form the two branches of a U having its base fastened to a frame of the headrest. In the second category, to which the present invention more specifically applies, the spindles are formed of metal rods which are individually connected to the headrest frame. The body or frame of the headrest then more and more often is a plastic frame or case having sleeves into which the spindles are engaged. In all cases, the frame is subsequently covered with upholstery (cushioning and cover).

FIG. 1very schematically shows a lateral view of a motor vehicle seat1of the type to which the present invention applies as an example. This seat comprises a seat bottom piece12on which is hinged a backrest14. The seat bottom piece is fastened to floor P of the vehicle, directly or via a guide rail mechanism16. Backrest14supports a headrest2formed of a body3and of spindles4having their free ends engaged in sleeves provided for this purpose in the high portion of backrest14.

FIG. 2is a rear perspective view of a usual headrest2′ of the type having separate spindles4′. The upper end of each spindle4′ is engaged in a sleeve32′ defined by head3′ of headrest2′. The ends of the spindles comprise holes intended to receive locking pins42′ transversely engaged through sleeves32′ and cooperating with grooves provided in the spindles. These pins are force-fit to block each spindle with respect to body3′.

A disadvantage of such an assembly is that it requires for an operator to force fit the two locking pins. Further, for security reasons, it is necessary to verify that the headrest is properly assembled. With this assembly principle, it must be attempted to force the separation of the spindle from the headrest to verify that it is properly fastened. A disadvantage is that in case of an incorrect fastening, the plastic frame is damaged and can no longer be used.

It would be desirable to simplify the assembly of spindles in a headrest of plastic-body type.

It would further be desirable to be able to easily verify that the headrest has been properly assembled.

Document EP-A-0743223 describes a headrest structure for a motor vehicle. The upper ends of the spindles of the headrests intended to be engaged into the housings of a body of the headrest comprise, on the one hand, a vertical rib cooperating with a vertical groove of the housing to guide the spindle while it is being introduced and, on the other hand, a horizontal rib cooperating with a horizontal tooth of the housing to block the translation of the spindle. Two different means are thus necessary on the spindle side and on the housing side, respectively for the guiding and to block the translation.

SUMMARY OF THE INVENTION

An object of an embodiment of the present invention is to provide a system for assembling spindles in the body of a headrest, which overcomes all or part of the disadvantages of conventional systems.

An object of another embodiment of the present invention is to avoid the use of force-fit pins to lock the spindles in the headrest body.

An object of another embodiment of the present invention is to provide a system in which an incorrect assembly can be easily detected.

To achieve all or part of these and other objects, the present invention provides a headrest for a motor vehicle seat, comprising:at least one spindle for assembling the headrest with a backrest of the seat; anda body provided with at least one housing in the shape of a sleeve for receiving one end of said spindle, the spindle comprising, in an upper portion, a shoulder capable of cooperating with a horizontal rib, protruding inside of a housing of the body, to block any translation of the spindle in its housing.

According to an embodiment of the present invention, the spindle comprises, at least in said upper portion, a cut-off corner emerging at its upper end.

According to an embodiment of the present invention, said rib cooperates with the cut-off corner of the spindle to form a mistake proof guide of the engagement of the spindle into the housing.

According to an embodiment of the present invention, each housing is open at its two ends, a tab, free at one of its ends and resiliently deformable, partially closing the upper opening of each housing and ending in a nose capable of cooperating with the cut-off corner of the corresponding spindle to block any rotation thereof in its housing.

According to an embodiment of the present invention, an upper surface of said tab is flush, at rest, with an upper surface surrounding the housing and forms an element for detecting that a spindle is locked.

According to an embodiment of the present invention, the spindle comprises a vertical port capable of cooperating with a resiliently deformable tongue of the body.

According to an embodiment of the present invention, the shoulder is formed by the upper edge of a horizontal rib made in the upper portion of the spindle.

According to an embodiment of the present invention, the horizontal rib of the spindle comprises a slanted lower edge.

The present invention also provides a motor vehicle seat comprising such a headrest.

The present invention also provides a method for assembling such a headrest, comprising the steps of:engaging the spindle into the body in a radial position where the cut-off corner faces the rib; androtating the spindle until the rib is in contact with said shoulder.

DETAILED DESCRIPTION

The same elements have been designated with the same reference numerals in the different drawings. For clarity, only those elements which are useful to the understanding of the present invention have been shown and will be described. In particular, the manufacturing of the spindles and of the head for receiving them has not been detailed, the present invention being compatible with usual methods for manufacturing metal spindles and plastic frames or the same in other materials. Further, the upholstery of the headrest has not been detailed either, the present invention being here again compatible with upholsteries currently associated with such headrests.

Reference will be made to terms front, back, bottom, top, upper, lower, etc., considering a headrest in a normal position of installation on a vehicle seat (for example, such as illustrated inFIG. 1).

FIG. 3is a rear perspective view of a headrest2according to an embodiment of the invention.

As previously, this headrest comprises a frame or body3, for example, a plastic frame, and two identical spindles4intended to be engaged into sleeves or housings32made in head3.

FIG. 4is a perspective view of an embodiment of a portion of body3of the headrest ofFIG. 3at the level of a sleeve32for receiving a spindle.

FIG. 5is a perspective view of an embodiment of an end of a spindle4intended to be engaged into sleeve32ofFIG. 4.

FIG. 6is a simplified top view of sleeve32ofFIG. 4.

The present invention will be described hereafter in relation with a single spindle and a single housing, the mechanism being the same for the two headrest spindles and being applicable to a single-spindle headrest.

Sleeve32has a generally cylindrical shape open at its two ends with a generally circular cross-section. In its upper portion, the sleeve emerges into a groove or recess36of a substantially planar portion34of body3.

Spindle4has a generally cylindrical shape of circular cross-section. It is contained within a diameter slightly smaller than the internal diameter of housing32to be able to engage therein. Spindle4comprises, in an upper portion and along a height preferably smaller than the height of housing32, a cut-off corner42. In other words, the section of the upper portion of the spindle is cut parallel to a diameter thereof.

In its upper portion, for example, approximately at mid-height of cut-off corner42, the spindle comprises a horizontal groove44. Groove44starts from cut-off corner42and extends along approximately one quarter of the spindle circumference. Groove44defines in its upper portion a shoulder47intended to cooperate with a horizontal rib38(FIG. 6), protruding from the inside of housing32to block any translation of the spindle. The position of cut-off corner42in the horizontal section of the spindle depends on the thickness of the rib in the horizontal section of the housing to enable the spindle to engage from the bottom and to pass rib38.

Preferably, a horizontal tab or tongue5partially closes, preferably diametrically, the upper opening of sleeve32. This tab is connected to body3by one of its ends52and is free in groove36at its other end. The free end of tab5comprises a downward-facing nose54. The upper surface of tab5is flush, at rest, with upper portion34of the region of body3around the groove. The volume of tab5is thus contained within recess36as more specifically appears fromFIG. 4. Tab5has a double function. On the one hand, its nose54takes part in the blocking of any rotation of spindle4. On the other hand, its deformation is used as a detector of the proper positioning of the spindle.

Another function of cut-off corner42is to cooperate with nose54of tab5to block any rotation of tube4. Thus, the length of tab5all the way to nose54is slightly greater than the partial diameter of spindle4on the direction tangent to cut-off corner42and running through the center of the spindle.

According to the position of rib38with respect to nose54, groove44may thus be on one side or the other of cut-off corner42.

FIG. 7is a simplified perspective view illustrating the engagement of spindle4in its housing32.

FIG. 8is a simplified perspective view illustrating the locked position of spindle4in its housing32.

FIG. 9is a perspective view of spindle4on the side of cut-off corner42.

As illustrated inFIG. 7, spindle4is engaged in tube32so that its cut-off corner42faces rib38. These two elements then behave as a mistake proof guide forcing the operator to engage spindle4in a correct position. When the spindle comes into contact with tab5, the continuation of the engagement of the spindle, associated with the fact that the cut-off corner does not face nose54, deforms tab5upwards. Once arrived in this position, the operator rotates spindle4(for example, by one quarter of a turn, counterclockwise) to bring cut-off corner42in front of nose54and thus block any rotation of spindle4. The external surface of cut-off corner42then cooperates with the internal surface of nose54. As illustrated inFIG. 9, the rotation of tube4also causes a vertical locking of its position by engaging rib38into groove44of the tube. Thus, both the rotation and the translation of the tube are blocked. Rib38is used, on the housing side, both to guide the spindle while it is being engaged, by cooperating with cut-off corner42, and to block any translation thereof, by cooperating with groove44.

According to the shown embodiment, tab5also behaves, during the engagement of the tube, as a vertical stop, the operator rotating the spindle after having slightly deformed tab5. As a variation, especially to mechanically relieve tab5, an additional vertical stop may be provided, for example, in the form of a rib protruding from recess36.

As appears fromFIG. 7, as long as the spindle has not been rotated to be blocked, tab5is slightly deformed upwards and thus protrudes from upper surface34of the housing. It is thus particularly easy to detect an incorrect assembly. Such a detection may be performed visually by an operator or by automated means, for example, a light beam which, if interrupted by tab5, indicates an incorrect assembly.

In the position ofFIGS. 8 and 9, when the tab has come back down, this necessarily means that spindle4has been turned in the right direction and thus can no longer either rotate or move vertically.

Spindles4may be made of metal, of plastic, or of a composite, and are preferably tubular. Head3is generally made of injected plastic (for example, expanded polypropylene). A single spindle supporting the headrest may be used.

The height of cut-off corner42of spindle4is at least equal to the distance between the high opening of housing32and rib38. Preferably, this height is at most equal to the height of the housing so that, once the spindle has been assembled, its visible portion is circular.

According to a preferred embodiment, tab or clip5is solid with head3, which is made of molded plastic. As a variation, tab5may be an insert made of a different material, for example, force fit by its end52into a horizontal hole of the head at the level of recess36.

The above-described spindle assembly system is particularly simple to implement. It is further easy to detect an incorrect assembly, be it manually or by automated means.

FIGS. 10 to 12show another embodiment of a groove44of the rod capable of cooperating with body3. These drawings should be compared withFIGS. 4 and 5and show, respectively, body3, rod4, and these two elements assembled. As compared with the embodiment ofFIG. 5, groove44comprises, at least in its low portion, no ridge or raw edge, but joins the section of greatest diameter of the rod by a slanted surface45. Once assembled (FIG. 12), rib38cooperates with shoulder47of groove44. Such an embodiment is compatible with the use, as a vertical lock, of the slanted-edge grooves currently used to adjust the height of the headrest.

FIG. 13is a perspective view of another embodiment of a portion of body3of the headrest ofFIG. 3at the level of a sleeve32′ for receiving a spindle.

FIG. 14is a perspective view of another embodiment of an end of a spindle4′ intended to be engaged into sleeve32′ ofFIG. 13.

As compared with the previous embodiments, spindle4′ comprises a vertical port48, for example, emerging at its upper end. Sleeve32comprises, in the vicinity of its upper end (for example, blind), a tongue39intended to cooperate with port48of spindle4′. Tongue39is capable of resiliently deforming, its rest position being inside of the sleeve, as illustrated inFIG. 13.

The other elements (cut-off corner, groove, rib) are not modified with respect to the other embodiments.

When it is engaged into sleeve32′, the external wall of spindle4′ presses tongue39and deforms it towards the outside. Once spindle4′ abuts against the bottom of sleeve32′, its rotation (for example, by one quarter turn) places port48in front of tongue39which resiliently enters into port48. Any rotation of spindle4′ is then blocked. To block its translation, like for the other embodiments, rib38cooperates with shoulder47of the spindle. Tongue39is obtained by molding, on manufacturing of body3, or is an insert.

Tongue39may comprise an external bump (not shown) forming an element of detection of an incorrect assembly, this bump protruding from the external surface of sleeve32′ as long as the tongue is not engaged into port48.

Various embodiments have been described, various alterations and modifications will occur to those skilled in the art. In particular, the practical implementation of the present invention is within the abilities of those skilled in the art based on the functional description given hereabove by using materials and tools currently used in the manufacturing of headrests. Further, the relative dimensions and positions of the various elements (grooves44, ribs38, tabs5, cut-off corners42, etc.) are within the abilities of those skilled in the art based on the indications relative to the mutual cooperation of these elements.