FR2978389A1 - Device for locking metallic rod associated with headrest at backrest of seat of car, has recess including side walls arranged to allow anchoring of block in recess relative to effort exerted on block upward or downward - Google Patents

Abstract

The device (1) has a metal locking part (7) including an insertion zone extending according to a horizontal plane. The zone is equipped with an insertion edge in a notch (3). The recess is filled by a block (12) of plastic material. The block is projected from the edge to form a shoe (11) that prevents contact between the part and a metallic rod (2) when the part is spaced from the notch while allowing insertion of the part in the notch. The recess includes two side walls arranged to allow anchoring of the block in the recess relative to effort exerted on the block upward or downward.

Description

The invention relates to a slidably locking device for a toothed rod of association of a headrest to a motor vehicle seat back and a seat or a headrest comprising such a device.

It is known to provide a sliding blocking device for a metal rod for associating a headrest with a motor vehicle seatback, said rod comprising at least one sliding locking notch, said device comprising a receiving sleeve of said sliding rod and, integral with said sleeve, a drawer made of molded plastic material 1 o mounted radially displaceable, said slide being forced in translation towards said sleeve by an elastic return means, said slide being provided with a metal detent piece, said piece being arranged to be able to engage, under the effect of said biasing means, in said notch when they are facing one another to lock said sliding rod. The presence of the metal detent piece is required in order to allow a notch resistant against vertical biasing of the rod during a shock of the head of the passenger on the headrest, particularly when the notch is shallow, for example less than 2.5 mm, this in order to limit the phenomenon of initiation of rupture on said rod.

In such an embodiment, the sliding of the rod in the sleeve, for example during a height adjustment of the headrest, leads to a situation where the notching piece slides against said rod. This results in a metal-to-metal friction leading to abrasion of the rod, which is detrimental in terms of aesthetics, and all the more so as the biasing means is powerful.

The object of the invention is to overcome this disadvantage.

For this purpose, and according to a first aspect, the invention proposes a device for slidably locking a metal rod of association of a headrest to a motor vehicle seat back, said rod comprising at least a sliding locking notch, said device comprising a sleeve for receiving said sliding rod and, integral with said sleeve, a drawer made of molded plastic material mounted to move in radial translation, said slide being constrained in translation towards said sleeve by a resilient return means, said slide being provided with a metal detent piece, said part being arranged to be able to engage, under the effect of said restoring means, in said notch when they are facing one of the another for locking said sliding rod, said part comprising an engagement zone extending in a substantially horizontal plane, said zone being provided with an engagement edge in said notch, said zone comprising a recess opening towards said edge, said recess being filled by a block of said plastic material coming from the material of said drawer, said block projecting from said edge so as to form a pad avoiding a contact between said piece and said rod 15 when said piece is remote from said notch while allowing engagement of said piece in said notch when facing each other, said recess comprising two lateral walls of geometries respectively arranged to allow anchoring said block in said recess by compared to a force exerted upwards or downwards. In this description, unless otherwise stated, the terms of positioning in the space (vertical, horizontal, high, low, high, low, ...) are taken in reference to the device arranged in the vehicle, the seat being in configuration. of use by a passenger with its substantially vertical file.

The two side walls of the recess are considered relative to the direction towards which said recess opens. They therefore correspond to the walls arranged opposite one another, starting from the engagement edge and pointing towards the bottom of the recess. With the proposed arrangement, the sliding of the rod in the sleeve leads to a situation where it is not the notching piece that slides against said rod but the block based on plastic material.

This results in a plastic against metal friction that does not create abrasion of the rod.

According to other aspects aspect, the invention provides a seat or a headrest comprising such a device.

Other features and advantages of the invention will appear in the description which follows, with reference to the appended figures in which: - Figure 1 is a schematic partial sectional view along the vertical plane P symmetry of the drawer shown in Figure 2, a device according to one embodiment, a rod being inserted into said device, said device being in the blocking configuration of the sliding of the rod, - Figure 2 is a schematic perspective view of the drawer of the device of Figure 1, said drawer being provided with a notching part; FIG. 3 is a perspective view of the notching part associated with the drawer of FIG. 2; FIG. 4 is a front detail view, in the direction of 2, provided with the notch part; FIG. 5 is a detail of FIG. 2 which is shown in side view instead of in sectional view.

Referring to the figures, there is now described a sliding blocking device 1 of a metal rod 2 of association of a headrest, not shown, to a seat back, not shown, of a motor vehicle, said rod comprising at least one sliding locking notch 3, said device comprising a sleeve 4 for receiving said sliding rod 4 and, integral with said sleeve, a slide 5 made of molded plastic material mounted to move in radial translation.

The drawer is constrained in translation towards said sleeve by an elastic return means 6, here in the form of a spring, said drawer being provided with a metal detent piece 7, said part being arranged to engage, under the effect said return means, in said notch when facing each other, for locking said sliding rod, said piece comprising a zone 8 of engagement extending in a substantially horizontal plane.

The zone 8 is provided with an engagement edge 9 in said notch, said zone comprising a recess 10 opening towards said edge, said recess being filled by a block 12 of said plastic material coming from said drawer material, said block projecting from said edge so as to form a pad 11 avoiding a contact between said piece and said rod when said piece is at a distance from said notch while allowing engagement of said piece in said notch when they are facing one another.

When talking about a commitment of the piece 7 in the notch 3 when they are facing each other, that means that part of the piece 7 is hidden by the notch 3 when is viewed in an axial view with reference to the axis of the rod 2. In the case of a rod 2 having a curvature, the axial view is considered with reference to the axis of said rod at the notch 3.

Thus, the piece 7 of notching can play its role of locking the rod 2 in sliding.

As shown in Figure 4, the recess 10 comprises two side walls 13 of geometries respectively arranged to allow anchoring of the block 12 in said recess with respect to a force exerted on said block upwardly or downwardly.

With such an arrangement, it ensures a perfect maintenance of the block 12 in the recess 10, even after a large number of sliding of the rod 2 which, because of its repeated friction against said pad, can at the long generate a creep of the plastic material causing a withdrawal of said shoe of said housing.

According to one embodiment, the block 12 is protruding from a dimension less than 0.5 mm, in order to guarantee a good engagement of the part 7 in the notch 3 when facing each other According to the embodiment shown, the engagement zone 8 extends over the entire part 7 of notching.

According to the embodiment shown, the engagement zone 8 is in the form of a plate, the recess 10 being in the form of a notch.

As shown in FIG. 4, the lateral walls 13 of the recess 10 are in the form of vertical walls whose upper and lower edges 17 are chamfered so as to receive a block 12 having upper and lower lateral overhangs 20 and anchoring said block.

Of course, it may be provided various embodiments to achieve the same result.

Not shown, and not exhaustive, can be provided: - a racking chamfers made on the edges 16,17 - a groove formed in each wall 13 - striations made in the walls 13, - a punching of the walls 13 , 30 - etc ... 10 6 As shown in Figure 5, the engagement edge 9 is in the form of a vertical wall whose upper edges 18 and lower 19 are chamfered.

Alternatively not shown, the chamfers on the edges 18,19 may have a shelf.

With such an arrangement, it is ensured that the ends of the notching member 7 are not likely to scratch the notches 3, such a situation may occur due to a slight potential rotation of the slide 5 relative to the translation 1 o radial expected, this due to the games provided in the device 1 between the sleeve 4 and said drawer to allow its translation.

FIG. 5 illustrates in particular that the gap 22 between the rod 2 and the piece 7 is accentuated by the fact that the borders 18, 19 are chamfered, such an accentuated deviation guaranteeing a non-contact metal / metal, contact which could occur in the absence of chamfers.

In a manner not shown, the engagement zone 8 is in the form of a metal wire, the recess 10 being in the form of a U-fold, the circular section 20 of the wire having a geometry making it possible to overcome the chamfers provided in the case of a plate.

According to the embodiment shown, the detent piece 7 is overmolded by the drawer 5. There is now described a motor vehicle seat comprising a backrest and a device 1, said device being mounted at the top of said backrest, so as to slidably receive a stem from a headrest.

Finally, a motor vehicle seat headrest comprising a support cushion and device 1 is described, said device being mounted in said cushion, so as to slidably receive a stem from a backrest. 25

Claims (10)

REVENDICATIONS1. Device (1) slidably locking a rod (2) of metal association of a headrest to a motor vehicle seat back, said rod comprising at least one notch (3) sliding lock, said device comprising a sleeve (4) for receiving said sliding rod and, secured to said sleeve, a drawer (5) made of molded plastic material mounted to move in radial translation, said slide being constrained in translation towards said sleeve by means of resilient return (6), said 1 o drawer being provided with a piece (7) metal detent, said part being arranged to be able to engage, under the effect of said restoring means, in said notch when they are in facing each other to block said sliding rod, said device being characterized in that said part comprises a zone (8) of engagement extending in a substantially horizontal plane, said zone being provided with a board (9) commitment in said notch, said zone comprising a recess (10) opening towards said edge, said recess being filled by a block (12) of said plastic material coming from said drawer material, said block projecting from said edge so as to form a pad (11) avoiding contact between said workpiece and said shank when said workpiece is spaced from said notch while permitting engagement of said workpiece in said notch when facing each other, said recess including two sidewalls ( 13) of geometries respectively arranged to allow an anchoring of said block in said recess with respect to a force exerted on said block upwards or downwards. 25 2. Device according to claim 1, characterized in that the block (12) is protruding from a dimension less than 0.5 mm, this to ensure a good engagement of the workpiece (7) in the notch (3) when they are opposite each other. 30 3. Device according to claim 1 or 2, characterized in that the engagement zone (8) extends over the entire part (7) of notching. 8 4. Device according to any one of claims 1 to 3, characterized in that the zone (8) of engagement is in the form of a wafer, the recess (10) being in the form of a notch. 5. Device according to claim 4, characterized in that the side walls (13) of the recess (10) are in the form of vertical walls whose upper (16) and lower (17) edges are chamfered so as to receive a block (12) having upper (20) and lower (21) lateral overhangs for anchoring said block. 6. Device according to any one of claims 4 or 5, characterized in that the edge (9) of engagement is in the form of a vertical wall whose upper edges (18) and lower (19) are chamfered. 7. Device according to any one of claims 1 to 3, characterized in that the zone (8) of engagement is in the form of a wire, the recess (10) being in the form of a U-fold . 8. Device according to any one of claims 1 to 7 characterized in that the piece (7) of notching is overmolded by the slide (5). 9. Motor vehicle seat comprising a backrest and a device according to any one of claims 1 to 8, said device being mounted at the top of said folder. 10. A motor vehicle seat headrest comprising a support cushion and device according to any one of claims 1 to 8, said device being mounted in said cushion.