WO2010058306A1

WO2010058306A1 - Assembly of receiving sheaths and seat comprising it

Info

Publication number: WO2010058306A1
Application number: PCT/IB2009/054777
Authority: WO
Inventors: Christophe Le Tinnier
Original assignee: I.T.W. De France
Priority date: 2008-11-24
Filing date: 2009-10-28
Publication date: 2010-05-27
Also published as: FR2938802A1

Abstract

The assembly of two receiving sheaths (1, 2) comprises two sheaths (1, 2) each including a hollow space (23, 35) for receiving a rod (3). The first sheath (1) guides a rod (3) exclusively in sliding and the second sheath (2) guides a rod (3) exclusively in a combination of sliding with a movement in translation transverse to the orientation of said second sheath (2). The seat includes a frame that includes two bushes and a headrest that includes the set of sheaths and has an inverted U-shaped frame (4) comprising two vertical branches. The second sheath (2) has two plane surfaces (36) and is accomodated in a position in which its two plane surfaces (36) are oriented parallel to a plane containing the axes of said two sheaths (1, 2). The seat includes indexing means for housing the second sheath (2) in said position in its bush.

Description

ASSEMBLY OF RECEIVING SHEATHS AND SEAT COMPRISING IT

The invention concerns in a general way sheaths receiving branches of a headrest of a seat, in particular a vehicle seat .

It is known that there exist seats including headrests provided with an inverted U-shaped frame and a cushion that envelops the horizontal branch and a portion of the vertical branches adjacent the horizontal branch.

The portion of each vertical branch that is not enveloped by the cushion forms a stem adapted to be pushed to a greater or lesser depth into receiving means that the seat-back of the seat includes.

The receiving means are fixed rigidly into the frame of the seat-back of the seat and include two bushes adapted to receive the stems of the frame. Given manufacturing tolerances, the distance between the vertical branches of the headrest does not always correspond perfectly to that of the bushes in the seat. Also, the bushes on the one hand and the vertical branches on the other hand are not always parallel to each other. In this situation, it is necessary to force the stems of the headrest into the bushes .

There is known from the document FR 2 881 088 a U- shaped headrest the horizontal branch of which includes two sections connected together by a flexible material so as to allow longitudinal and/or angular offsetting of these sections. This headrest is satisfactory in terms of allowing the distance between the vertical branches to be matched to the distance between the bushes into which they are inserted, the axis of each vertical branch being aligned with that of the corresponding bush.

The object of the invention is to provide an assembly of sheaths for receiving the branches of a headrest that compensates defects of separation or of parallelism whilst remaining particularly, simple, convenient and economical to produce. To this end, the invention proposes an assembly of two sheaths for receiving a rod of a headrest for a seat, notably a vehicle seat, each intended to be housed in a respective one of two bushes belonging to a seat frame, each of said sheaths including a hollow space for slidingly receiving a respective one of said rods that is cylindrical and of predetermined diameter, characterized in that a first of said sheaths guides one of said rods exclusively in sliding and a second of said sheaths guides one of said rods exclusively in a combination of sliding with movement in translation transverse to the orientation of said second sheath.

An assembly of two sheaths of this kind is used in a seat with the second sheath positioned so that the plane of movement in translation of the rod in the second sheath passes through the axes of the sheaths. On insertion of the rods belonging to the vertical branches of the inverted U-shaped frame of the headrest, the user feels no radial clearance because one of the rods is guided exclusively in sliding. The possibility of movement in translation in a plane that is the plane of the frame thus compensates defects in respect of the separation and parallelism of the rods and/or the sheaths . According to implementation features that are particularly simple and convenient as much for manufacture as in use :

- said hollow space of said second sheath has two plane surfaces separated by a distance equal to said predetermined diameter; said hollow space of said second sheath has, alternating with said two plane surfaces, two rounded surfaces each having a diameter equal to said predetermined diameter; - said hollow space of said first sheath has on its surface three axial ribs regularly distributed over that surface, said ribs delimiting a cylindrical housing of said predetermined diameter;

- said ribs extend from one end to the other of said first sheath;

- each of said sheaths is molded in one piece from plastic material; the set has on each of said sheaths a fixing mechanism for a respective one of said branches for adjusting the height of the headrest.

The invention also proposes a seat, notably a vehicle seat, including a frame that includes two bushes and a headrest that has an inverted U-shaped frame comprising two vertical branches and one horizontal branch, each of said vertical branches comprising a rod, characterized in that it also includes an assembly of sheaths as described above, each of said rods being housed in a respective one of said sheaths and each of said sheaths being housed in a respective one of said bushes with said second sheath housed in a position in which its two plane surfaces are oriented parallel to a plane containing the axes of said two sheaths, and in that said seat includes indexing means for housing said second sheath in said position in the respective sheath. According to implementation features that are particularly simple and convenient as much for manufacture as in use :

- said frame is of metal, in one piece and has a circular section; - said headrest further includes a cushion covering the horizontal branch of the frame and a portion of each vertical branch of the frame adjoining said horizontal branch, each branch having a portion inserted more or less deeply into a respective one of said sheaths. The features and advantages of the invention will emerge from the following description, given by way of preferred but nonlimiting example, with reference to the appended drawings, in which:

- figure 1 is a diagrammatic perspective view of an assembly of the invention with a headrest frame positioned in the sheaths;

- figure 2 is a view from below of the assembly and the frame from figure 1;

- figure 3 is a view in elevation of the assembly and the frame from figure 1 ;

- figure 4 is a view of the assembly in section taken along the line IV-IV in figure 2, the assembly being shown fixed in a frame portion with the sheaths receiving a branch and with the branch fixing mechanism; - figure 5 is a view in perspective of a headrest with branches adapted to be received in an assembly of the invention; and

- figure 6 is a perspective view of a seat of the invention. The assembly of two receiving sheaths of the invention includes two sheaths 1, 2 each molded in one piece from plastic material. Each sheath 1, 2 is adapted to receive a branch 3 of a frame 4 of a headrest 5 of a seat 6. Each sheath 1, 2 is received in a bush 7 belonging to a frame 8 of the seat 6. The frame 8 is positioned in the seat-back of a seat 6.

The sheath 1 has three main parts: a head 10, a body 11 and a foot 12 (fig. 4) . On the same side as the end of the sheath 1, the head 10 includes a flange 13. The rest of the head 10, on the same side as the body 11, has a diameter substantially equal to the outside diameter of the bush 7. There is a first annular shoulder 15 between the flange 13 and the rest of the head 10.

There is a second annular shoulder 16 between the head 10 and the body 11. The shoulder 16 is the same shape as the annular end of the bush 7 and forms an abutment for the sheath 1 against the end of the bush 7 when the sheath 1 is inserted into the bush 7.

The sheath 1 is extended by the body 11, the cylindrical shape of which is fitted to that of the bush 7, i.e. the outside diameter of the body 11 matches the inside diameter of the bush 7.

The sheath 1 further includes the foot 12, which is cylindrical . The interior surface of the foot extends the interior surface of the body 11. The foot 12 includes two opposed rectangular windows. Inside each window there is a lug 20 with substantially the same dimensions as the window. Each lug 20 is retained along its edge close to the free end of the foot 12 and extends outward from that edge.

A fixing mechanism 22 represented diagrammatically in figure 4 is provided at the end of the sheaths 1, 2 opposite to the feet 12. This mechanism 22 retains the headrest 5 in position in the sheaths 1, 2. The mechanism 22 includes a sliding member 25 having a portion (not visible) that can be maneuvered between a position in which it is engaged with the foot 12 in a notch 26 of the branch 3 and a position in which it is located outside the area of sliding of the foot 12. One such mechanism is described in the document EP 0 798 157, for example.

The assembly includes a second sheath 2 with the same as the sheath 1 described hereinabove.

The sheath 1 has a hollow space 23 that extends from one end to the other. The hollow space 23 is cylindrical. It has a diameter 24 that is slightly greater than the diameter of the branches 3 of the frame 4.

The sheath 1 includes three rectilinear ribs 27 here extending from one end to the other of the hollow space 23 on the surface of the hollow space 23. The three ribs 27 are distributed at equal angles over the surface, i.e. there is an angle of 120° between two successive ribs 27. The ribs 27 each have a rounded cross section such that each has a rectilinear summit. The summits of the three ribs 27 define a cylindrical housing 30, i.e. a cylinder, and in particular a frame branch, can be accommodated in the hollow space 23 bearing against the three ribs 27. The diameter 31 of the cylindrical housing 30 is slightly less than the diameter 24 of the hollow space 23 and equal to the diameter 32 of the branches 3.

The sheath 2 has a rectilinear hollow space 35 the cross section of which is of oblong shape. The hollow space 35 has two facing plane surfaces 36 separated by a distance corresponding to the diameter 32 of the branches 3. The surfaces 36 have a width slightly less than the diameter 32. The two surfaces 36 are connected to each other by rounded surfaces 37. Each rounded surface 37 globally corresponds to the interior surface of a cylinder cut in two in an axial plane. The diameter of the surfaces 37 is equivalent to the diameter 31 of the cylindrical housing 30. The hollow space 35 can thus accommodate a cylinder, and in particular a frame branch, of diameter 31, with the cylinder in rectilinear bearing engagement against each of the two surfaces 36. If the axis of the cylinder is angularly offset from that of the hollow space 35, the cylinder can further come into point contact with one and/or the other of the surfaces 37. Also, the cylinder is free to slide in the direction of the axis of the hollow space 35 and to move in translation in a direction transverse to that axis.

The headrest 5 includes a cushion 40 and the frame 4. The frame 4 has an inverted U-shape comprising a horizontal branch and the two vertical branches 3.

The cushion 40 envelopes part of the frame 4 and exposes only two feet of the vertical branches 3 each adapted to be inserted to a greater or lesser depth into one of the sheaths 1, 2 of the receiving assembly that the seat -back of the seat 6 for which the headrest 5 is designed includes. Here the frame 4 is of metal, the three branches constituting it being obtained by bending a single metal bar so that the vertical branches are rods.

Each branch 3 is provided with a series of notches 26. The notches 26 are adapted to cooperate with the fixing mechanism 22 provided on the sheaths 1, 2. The sliding member 25 of the mechanism 22 can be moved between the position in which it engages in a notch 26 of the branch 3 and a position in which it is outside the area of sliding of the branch 3. The sheaths 1, 2 are disposed toward the top of the seat-back of the seat so that the two hollows spaces 23, 35 have their end on the same side as the flange 13 toward the outside of the seat 6.

The bush 7 that is intended to receive the sheath 2 is provided with indexing means so that the surfaces 36 are disposed in planes each of which is parallel to the plane containing the two axes of the bushes 7 or the sheaths 1, 2.

Here the indexing means (not shown) include a rectilinear groove on the bush 7 and a projection on the sheath 2 adapted to slide in the groove on the bush 7 with the groove and the projection disposed so that, when the sheath 2 is in the bush 7, the surfaces 36 are parallel to the plane containing the two axes of the bushes 7.

To fix the sheaths 1, 2 in the bushes 7, the sheaths 1, 2 are brought near the bushes 7 with the end of the sheaths 1, 2 comprising the foot 12 ahead. The lugs 20 of the foot 12 retract on insertion of the sheath 1, 2 into the bush 7 and the sheath 1, 2 is pushed in until the shoulder 16 come up against the upper end of the bush 7.

The lugs 20 then move slightly away from the windows in the foot 12 so that the sheath 1, 2 is retained between the shoulder 16 and the lugs 20.

In a variant of this embodiment that is not shown, the sheath is fixed into the bush without being clipped by lugs, for example with a force fit or fixed by screws.

The insertion of the branches 3 of the headrest 5 in the sheaths is described next. The branches 3 are inserted into the sheaths 1, 2 via the openings of the latter at the same end as the head 10. The branch 3 that is inserted in the sheath 1 is then in contact with the three ribs 27 and can slide in axial translation. At the same time the branch 3 that is inserted in the sheath 2 is in contact with each of the plane surfaces 36. The contact between the branch 3 and each plane surface 36 is along a straight line parallel to the axis of the branch 3. If the two branches 3 are parallel to each other, contact in the sheath 2 is along two straight lines that are also parallel to the axis of the sheath 2.

If the distance between the axis of the branches 3 corresponds to the distance between the axis of the sheaths 1, 2, a space is left free between the branch 3 and each of the rounded surfaces 37.

If the distance between the axis of the branches 3 is slightly greater than that between the axis of the sheaths 1, 2, the branch 3 is positioned closer to the rounded surface 37 opposite to the sheath 1, or even against that rounded surface 37.

If not, the branch 3 is positioned closer to the surface 37 of the sheath 2 on the same side as the sheath 1, or even against that surface 37. If the two branches 3 are contained within the main plane of the frame 4 but are not perfectly parallel to each other, on insertion one of the two branches 3 will be inserted in the sheath 1 with the axis of the branch 3 positioned coaxially with the axis of the sheath 1 and the axis of the branch 3 that is inserted in the sheath 2 will be angularly offset to one side or the other relative to the axis of the sheath 2.

Thanks to the oblong shape of the section of the hollow passage 35, the branch 3 can nevertheless be easily inserted since the bearing engagement with the plane surfaces 36 will always be along two straight lines with the branch 3 positioned at a greater or lesser distance from one or the other of the rounded surfaces 37 according to whether that distance is measured near or far away from the free end of the branch 3.

For example, if this branch 3 is slightly oriented toward the other branch, on the same side as the end of the sheath 2 and to be more precise on the same side as the foot 12 of the sheath 2, the branch 3 will be here close to the rounded surface 37 that is on the same side as the sheath 1 whereas on the same side as the flange 13 the branch 3 will be farther away from that rounded surface .

Conversely, if the branches diverge slightly on the same side as the foot 12 of the sheath 2, the branch will be closer to the rounded surface 37 that is on the opposite side to the sheath 1 near the foot 12 of the sheath 2.

If both branches were subject to a defect of parallelism with an angular offset around the horizontal branch, then both branches 3 would no longer be in the same main plane of the frame 4. To take this possible defect of parallelism into account, the bushes 7 can be mounted to pivot slightly, for example around the section 42 represented diagrammatically in figure 4. The pivoting mechanism is not represented.

The assembly of sheaths of the invention therefore take into account defects of parallelism of the branches of the headrest frame in a simple and convenient manner without it being necessary to provide a frame in several parts for example joined together flexibly.

In a variant of the above embodiment , the ribs do not extend the full height of the interior surface of the sheaths 1, 2. These ribs extend from the end on the same side as the flange and are interrupted at a distance from the opposite end.

In another variant of the above embodiment, the sheath 1 includes a greater number of ribs, for example four ribs . In another variant of the above embodiment, the branches 3 are not cylinders of circular section but have a polygonal section with a large number of facets, for example twelve facets.

In a variant of the above embodiment, the vertical branches and where applicable the horizontal branch include a cylindrical plastic material shell molded onto a metal rod.

The present invention is not limited to the embodiment described and shown and encompasses any execution variant.

Claims

1. Assembly of two sheaths (1, 2) for receiving a rod (3) of a headrest (5) for a seat (6), notably a vehicle seat, each intended to be accomodated in a respective one of two bushes (7) belonging to a seat frame (8), each of said sheaths (1, 2) including a hollow space (23, 35) for slidingly receiving a respective one of said rods (3) that is cylindrical and of predetermined diameter, characterized in that a first of said sheaths (1) guides one of said rods (3) exclusively in sliding and a second of said sheaths (2) guides one of said rods (3) exclusively in a combination of sliding with movement in translation transverse to the orientation of said second sheath (2) .

2. Assembly according to claim 1, characterized in that said hollow space (35) of said second sheath (2) has two plane surfaces (36) separated by a distance equal to said predetermined diameter.

3. Assembly according to claim 2, characterized in that said hollow space (35) of said second sheath (2) has, alternating with said two plane surfaces (36) , two rounded surfaces (37) each having a diameter equal to said predetermined diameter.

4. Assembly according to any of claims 1 to 3 , characterized in that said hollow space (23) of said first sheath (1) has on its surface three axial ribs (27) regularly distributed over that surface, said ribs (27) delimiting a cylindrical housing (30) of said predetermined diameter.

5. Assembly according to claim 4, characterized in that said ribs (27) extend from one end to the other of said first sheath (1) .

6. Assembly according to any of claims 1 to 5 , characterized in that each of said sheaths (1, 2) is molded in one piece from plastic material.

7. Assembly according to any of claims 1 to 6, characterized in that it has on each of said sheaths (1, 2) a fixing mechanism (22) for a respective one of said branches (3) for adjusting the height of the headrest (5) .

8. Seat, notably vehicle seat, including a frame (8) that includes two bushes (7) and a headrest (5) that has an inverted U-shaped frame (4) comprising two vertical branches and one horizontal branch, each of said vertical branches comprising a rod (3) , characterized in that it also includes an assembly of sheaths according to any of claims 2 to 7, each of said rods (3) being accomodated in a respective one of said sheaths (1, 2) and each of said sheaths (1, 2) being housed in a respective one of said bushes (7) with said second sheath

(2) housed in a position in which its two plane surfaces

(36) are oriented parallel to a plane containing the axes of said two sheaths (1, 2) , and in that said seat includes indexing means for housing said second sheath

(2) in said position in the respective sheath (7) .

9. Seat according to claim 8, characterized in that said frame (4) is of metal, in one piece and has a circular section.

10. Seat according to claim 9, characterized in that said headrest (5) further includes a cushion (40) covering the horizontal branch of the frame and a portion of each vertical branch of the frame adjoining said horizontal branch, each branch having a portion inserted more or less deeply into a respective one of said sheaths (1, 2) .