FR3078928A1 - ANTI-EJECTION GUIDING DEVICE FOR A VEHICLE SEAT HEADREST - Google Patents

Abstract

The present invention relates to a guide device for a seat headrest, comprising two parallel rods (110, 120) intended to be associated with said headrest, two parallel guide members (130, 140) intended to be associated with the headrest. frame of the seat back and slidably receiving said rods (110, 120), and a locking mechanism comprising two notches (111, 121) made at the same height in said rods (110, 121), two drawers (135) mounted radially sliding in two housings (136, 146) formed in said guide members (130, 140) and comprising locking elements (137, 147) arranged to be able to engage said notches so as to lock said rods reversibly. sliding, as well as elastic return means (138, 148) formed in said recesses and urging said drawers so as to cause the engagement of said locking elements in said notches when this t elements are next to these notches.

Description

ANTI-EJECTION GUIDE DEVICE FOR. VEHICLE SEAT SUPPORT.

Field of the invention

The present invention relates generally to the field of head restraints, and in particular that of mounting such head restraints on the back of a vehicle.

Invention background

Motor vehicle seats are generally equipped with head restraints to ensure the comfort and safety of passengers.

Such a headrest is generally slidably mounted on the seat back by means of a guide device comprising two parallel rods intended to be associated with the headrest, as well as two parallel guide members intended to be associated with the back frame and each comprising a tubular reception sleeve for sliding a corresponding rod.

Each guide member also comprises a circular head surmounting the tubular sheath and projecting radially from the latter towards the outside.

This head makes it possible in particular to improve the level of finish by defining a covering edge intended to rest, after assembly of the guide member, on the top of the padding of the backrest.

In order to improve ergonomics of use, certain guide devices are provided with an axial sliding blocking mechanism making it possible to lock the headrest in at least one predefined upper limit position.

Such a mechanism comprises at least one notch formed in one of the rods as well as a drawer mounted with radial sliding in a housing formed in the head of the corresponding guide member.

The drawer includes a locking element arranged to be able to engage in the notch so as to reversibly lock the sliding rod.

The locking mechanism also includes elastic return means formed in the head housing and urging the drawer so as to cause the engagement of the locking element in the notch when this locking element is located opposite this notch. in order to lock the headrest in the corresponding position.

To lower the headrest, the user must exert with one of the fingers of one of his hands a radial pressure on the drawer against the elastic return means so as to disengage the locking element guts; then, while maintaining the pressure exerted on the drawer, then push this headrest axially downwards with his other hand so as to make it slide.

In the event of a sudden deceleration of the vehicle or impact from the front, the headrest is strongly stressed upwards under the effect of its mass and inertia, which can lead to the disengagement of the locking element notch and ejecting the rods from the guide members.

The headrest, which is thrown forward, may strike a passenger's head and cause them potentially serious injury.

In order to reduce the risks of projection of the headrest, patent application EP 1 955 893 discloses such a locking mechanism in which the drawer has a surface intended to cooperate, when the locking element is engaged in the notch, with a complementary abutment surface formed in the housing of the head so as to transform an axial force upwards on the rod into a radial force of engagement of the locking element in the notch.

However, in use, this solution proves to be insufficiently effective in preventing the disengagement of the rods from the notch locking element and the ejection of the rods from the guide members.

Subject and summary of the invention

The present invention therefore aims to improve the situation.

To this end, it offers a guide device for a headrest of a vehicle seat, comprising first and second parallel rods intended to be associated with said headrest, first and second parallel guide members intended to be associated with the back frame of said seat and respectively receiving said first and second rods by sliding, and an axial sliding locking mechanism making it possible to lock said headrest in at least one predefined position, said mechanism comprising at least one first notch practiced in said first rod, a first drawer mounted to slide radially in a first housing formed in said first guide member and comprising a first locking element arranged to be able to engage in said first notch so as to reversibly lock said first sliding rod, as well as the first elastic return means provided s in said first housing and urging said first drawer so as to cause the engagement of said first locking element in said first notch when this locking element is opposite this notch;

characterized in that said mechanism also comprises a second notch formed in said second rod at the same height as that of said first notch, a second drawer mounted with radial sliding in a second housing formed in said second guide member and comprising a second element locking arranged to be able to engage in said second notch so as to reversibly lock said second sliding rod, as well as second elastic return means formed in said second housing and urging said second drawer so as to cause the engagement of said second element locking in said second notch when this locking element is located opposite this notch.

By providing a double locking of the rods ensured by the abutment cooperation between the two locking elements and the two lower shoulders of the notches, the guide device according to the invention makes it possible to effectively retain these rods so as to prevent their ejection from the organs. guides and thus avoid any risk of projection of the headrest towards the front in the event of sudden deceleration of the vehicle or impact from the front.

According to preferred characteristics of the guiding device according to the invention, taken alone or in combination:

- Said second notch is delimited in the upper part by an upper guide ramp inclining upwards in the direction of the external surface of said second rod and capable of cooperating sliding with said second locking element;

- Said first notch is delimited in the upper part by a horizontal upper shoulder capable of cooperating in abutment with said first locking element;

- Said first and second notches are each delimited in the lower part by a horizontal lower shoulder capable of cooperating in abutment with a said corresponding locking element;

- Said first and second notches are each delimited radially by a recessed surface extending in a vertical plane perpendicular to the sliding axis of said corresponding drawer;

- Said first rod comprises one or more other notches similar to said first notch and arranged above the latter so as to allow said headrest to be locked in one or more intermediate positions between said predefined position and a low limit position in which it rests against the top of said backrest (2);

each of said guide members comprises a tubular sleeve for receiving with sliding of a respective rod intended to be received at least partially in a corresponding cylindrical sleeve integral with the frame of said backrest, as well as an annular head surmounting said corresponding sleeve in projecting radially from the latter and being intended to rest on the top of said backrest;

- said housings slidingly receiving said drawers are formed in said heads of the guide members; and or

- Said first and second elastic return means each consist of a respective V-shaped leaf spring comprising a first tongue rigidly connected to the corresponding drawer as well as a second tongue articulated elastically pivotally at one end of said first tongue by a bent intermediate portion forming the point of the V.

The invention also relates in a second aspect to a motor vehicle seat comprising a backrest on which a headrest is slidably mounted by means of such a guide device.

Brief description of the drawings

The description of the invention will now be continued with the detailed description of an exemplary embodiment, given below by way of illustration but not limitation, with reference to the appended drawings, in which:

- Figure 1 is a perspective view of the upper part of a motor vehicle seat comprising a headrest slidably mounted on the backrest by means of a guide device according to the invention;

- Figure 2 shows a partial view in vertical cross section of the guide device of Figure 1 showing the locking elements of the drawers engaged in the notches of the rods; and

- Figure 3 is a view similar to Figure 2 but showing the locking elements of the drawers outside the notches of the rods.

Detailed description of an embodiment

Figure 1 shows the upper part of a seat 1 of a motor vehicle on the back 2 of which is slidably mounted a headrest 3 by means of a guide device 10 according to the invention.

We will now describe in more detail the guide device 10 using FIG. 2.

In the remainder of this description and by convention, the terms "lower", "upper", "high" and "low" will be defined relative to the mounting position of such a guide device in the passenger compartment of a vehicle.

The guide device 10 comprises two parallel rods 110, 120 associated with the headrest 3, as well as two parallel guide members 130, 140 associated with the frame of the backrest 2.

Each guide member 130, 140 comprises a tubular receiving sleeve 131, 141 with sliding of a respective rod 110, 120, intended to be received at least partially in a corresponding cylindrical socket 5, 6 secured to the frame of the backrest 2 .

Each of the sleeves 131, 141 includes latching means 132, 142 able to cooperate with a socket 5, 6 in order to make the corresponding guide member 130, 140 integral with the backrest frame 2 and thus prevent its withdrawal.

These latching means here consist of a tongue 132, 142 formed in the cylindrical wall of the sleeve 131, 141 and designed to snap into a corresponding recess formed in the socket 5, 6.

Each of the sleeves 131, 141 also comprises an annular flange 133, 143 projecting radially outwards and intended to come to rest in abutment on the upper end edge of a corresponding socket 5, 6 after the tabs 132 are snapped in, 142, so as to prevent the complete insertion of these sleeves 131, 141 into the sockets 5, 6.

Each guide member 130, 140 also includes an annular head 134, 144 surmounting the tubular sleeve 131, 141, and projecting radially from the latter towards the outside.

As illustrated in FIG. 1, these heads 134, 144 make it possible in particular to improve the level of finish by defining overlapping edges intended to rest, after assembly of the guide members 13, 14, on the top of the backrest 2.

In order to improve the ergonomics of use, the guide device 10 integrates an axial sliding locking mechanism making it possible not only to lock the headrest 3 in at least one predefined upper limit position but also to avoid any risk. ejection of this headrest 3 in the event of sudden deceleration of the vehicle or impact from the front.

This mechanism comprises, in a known manner, a notch 111 formed in the rod 110 as well as a drawer 135 mounted to slide radially in a housing 136 formed in the head 134 of the corresponding guide member 130.

As illustrated in FIG. 3, the notch 111 is delimited radially by a recessed surface 111A extending in a vertical plane perpendicular to the radial sliding axis of the drawer 135, in the lower part by a lower shoulder 111B s' extending in a horizontal plane, and in the upper part by an upper shoulder 111C extending in a horizontal plane opposite the lower shoulder 111B.

The drawer 135 comprises a locking element 137 arranged to be able to engage in the notch 111 so as to reversibly lock the rod 110 in sliding in the two axial directions.

Elastic return means 138 formed in the housing 136 urge the drawer 135 so as to cause the engagement of the locking element 137 in the notch 111 when this locking element is located opposite this notch in order to lock the headrest 3 in the upper limit position.

These elastic return means are constituted by a V-shaped leaf spring 138, partially visible in FIGS. 2 and 3, and comprising a first tongue rigidly connected to the drawer as well as a second tongue hinged elastically with pivoting at one end of the first tab by a bent intermediate portion forming the point of the V.

This second elastic tongue which projects radially outside the drawer 135 comes to bear against the internal lateral wall of the housing 136 so as to permanently exert a radial stress on this drawer 135.

According to the invention, the locking mechanism also comprises a notch 121 formed in the rod 120 at the same height as the notch 111 in the rod 110, as well as a drawer 145 mounted to slide radially in a housing 146 formed in the head 144 of the corresponding guide member 140.

The notch 121 is delimited radially by a recessed surface 121A extending in a vertical plane perpendicular to the sliding axis of the drawer 145, in the lower part by a lower shoulder 121B extending in a horizontal plane, and in the upper part by an upper guide ramp 121C extending in a plane inclining upwards in the direction of the external cylindrical surface of the rod 120.

The drawer 145 comprises a locking element 147 arranged to be able to engage in the notch 121 so as to reversibly lock the rod 120 in sliding only in the axial direction oriented upwards.

Elastic return means 148 formed in the housing 146 (and similar to those 138 formed in the housing 136) urge the drawer 145 so as to cause the engagement of the locking element 147 in the notch 121 when this locking element is next to this notch.

The guide device 10 according to the invention thus allows the user to slide the headrest 3 between a low limit position in which the latter rests against the top of the backrest 2, and a high limit position where the elements of locking 137, 147 of the drawers 135, 145 are engaged in the notches 111, 121 of the rods 110, 120 (FIG. 2).

In the event of sudden deceleration of the vehicle or impact from the front, the rods 110, 120 undergo, under the effect of the mass and the inertia of the headrest 3, an axial upward force driving them sliding so that this headrest 3 reaches its upper limit position.

Once this position has been reached, the double locking of the rods 110, 120 ensured by the cooperation in abutment between the two locking elements 137, 147 and the two lower shoulders 111B, 121B of the notches 111, 121 makes it possible to effectively retain the rods 110, 120 and to prevent their ejection from the guide members.

Furthermore, the fact that the notch 121 has an upper inclined guide ramp 121C allows a user to lower the headrest 3 without external assistance, exactly in the same way as with the guide devices of prior art.

To do this, the user must thus exert with one of the fingers of one of his hands a radial pressure on the drawer 135 against the elastic return means 138 so as to disengage the locking element 137 notch 111; then, while maintaining the pressure exerted on the drawer 135, push axially downwards this headrest 3 with his other hand so as to make it slide as illustrated in FIG. 3 (the locking element 147 disengaging then by itself of the notch 121 sliding along the upper inclined guide ramp 121C).

According to variants not shown, the rod 110 includes one or more other notches similar to the notch 11 and formed at regular intervals above the latter, so as to allow the user to lock the headrest in one or several intermediate positions between its upper limit position and its lower limit position.

According to other variants not shown, the elastic return means urging the drawers are different and for example constituted by helical compression springs.

Finally, it should be remembered that the present invention is not limited to the embodiments described and shown, but that it encompasses any other variant embodiment.

Claims (10)

1. Guide device for headrest (3) of seat (1) of vehicle, comprising first and second parallel rods (110, 120) intended to be associated with said headrest (3), a first and a second parallel guide members (130, 140) intended to be associated with the frame of the backrest (2) of said seat (1) and receiving said first and second rods (110, 120) with sliding respectively, and a sliding locking mechanism axial enabling said headrest (3) to be locked in at least one predefined position, said mechanism comprising at least a first notch (111) formed in said first rod (110), a first drawer (135) mounted in radial sliding in a first housing (136) formed in said first guide member (130) and comprising a first locking element (137) arranged to be able to engage in said first notch (111) so as to reversibly lock said first rod (110) sliding, as well as first elastic return means (138) formed in said first housing (136) and urging said first drawer (135) so as to cause the engagement of said first locking element (137) in said first notch ( 111) when this locking element (137) is located opposite this notch (111); characterized in that said mechanism also comprises a second notch (121) formed in said second rod (120) at the same height as that of said first notch (111), a second drawer (145) mounted in radial sliding in a second housing ( 146) formed in said second guide member (140) and comprising a second locking element (147) arranged to be able to engage in said second notch (121) so as to reversibly lock said second rod (120) in sliding, thus that second elastic return means (148) formed in said second housing (146) and urging said second drawer (146) so as to cause the engagement of said second locking element (147) in said second notch (121) when this locking element (147) is located opposite this notch (121). 2. Guide device according to claim 1, characterized in that said second notch (121) is delimited in the upper part by an upper guide ramp (121C) inclining upwards towards the external surface of said second rod (120) and able to cooperate with sliding with said second locking element (147). 3. Guide device according to one of claims 1 or 2, characterized in that said first notch (111) is delimited in the upper part by a horizontal upper shoulder (111C) able to cooperate in abutment with said first locking element ( 137). 4. Guide device according to one of claims 1 to 3, characterized in that said first and second notches (111, 121) are each delimited in the lower part by a horizontal lower shoulder (111B, 121B) able to cooperate in abutment with a said corresponding locking element (137, 147). 5. Guide device according to one of claims 1 to 4, characterized in that said first and second notches (111, 121) are each delimited radially by a recessed surface (111A, 121A) extending in a vertical plane perpendicular to the sliding axis of said corresponding drawer (135, 145). 6. Guide device according to one of claims 1 to 5, characterized in that said first rod (110) comprises one or more other notches similar to said first notch (111) and formed above the latter so as to allow lock said headrest (3) in one or more intermediate positions between said predefined position and a low limit position in which it rests against the top of said backrest (2). 7. Guide device according to one of claims 1 to 6, characterized in that each of said guide members (130, 140) comprises a tubular sleeve (131, 141) for sliding reception of a respective rod (110, 120) intended to be received at least partially in a corresponding cylindrical socket (5, 6) integral with the frame of said backrest (2), as well as an annular head (134, 144) surmounting said corresponding sleeve (131, 141) projecting radially from the latter and being intended to rest on the top of said backrest (2). 8. Guide device according to claim 7, characterized in that said housings (136, 146) slidingly receiving said drawers (135, 145) are formed in said heads (134, 144) of the guide members (130, 140) . 9. Guide device according to one of claims 1 to 8, characterized in that said first and second elastic return means (138, 148) each consist of a respective V-shaped leaf spring comprising a first tongue linked rigidly to the corresponding drawer (135, 145) as well as a second tongue articulated elastically pivotally at one end of said first tongue by an angled intermediate portion forming the point of the V. 10.A motor vehicle seat comprising a backrest (2) on which a headrest (3) is slidably mounted by means of a guide device according to one of claims 1 to 9.