MOTOR VEHICLE SEAT CUSHIONING

Abstract

The invention is motor vehicle cushioning having a cushion and a flexible layer for detecting the presence of an occupant in the seat. The cushioning includes a cap covering the cushion, the cap is mounted on the cushion, covering the layer. The layer is made from an elastically stretchable sheet on which an electric circuit made from conductive ink is printed, the layer being separate from the cap and glued, at least partially, by the underside of the sheet, to the cushion, so as to stretch when the cushion is deformed upon receiving an occupant, and to consequently stretch the circuit in such a way as to increase the electrical resistance of same.

Claims

1. A motor vehicle seat cushioning, the cushioning comprising: a padded cushion made from elastically compressible foam, a flexible layer adapted for detecting the presence of an occupant in the seat, the layer being arranged on the cushion on a face for receiving the occupant, the layer being made from a sheet on which an electric circuit made from conductive ink is printed, the ink being made from conductive particles embedded in an elastically insulating binder, the circuit being intended to be supplied by a generator, a cap covering the cushion, the cap being mounted on the cushion covering the layer, the cap being provided with return means fastened on reciprocal means secured to the cushion and peripheral fastening means intended to cooperate with reciprocal means outside of the cushioning provided on the seat, the cushioning wherein: the sheet is elastically stretchable, the layer is firstly separate from the cap and secondly glued, at least partially, by the underside of the sheet, to the cushion, adapted to stretch when the cushion is deformed upon receiving an occupant, and to consequently stretch the circuit in such a way as to increase the electrical resistance of same.

2. The cushioning according to claim 1, wherein the underside of the sheet is glued at least by one portion of the periphery of the cushioning, along two opposite edges, on the cushion.

3. The cushioning according to claim 1, wherein the underside of the sheet is glued totally on the cushion.

4. The cushioning according to claim 1, wherein the sheet is elastically stretchable in at least one direction by at least 5% with respect to the dimension of the cushioning along the direction when it is not stretched.

5. The cushioning according to claim 1, wherein the sheet is made from textile.

6. The cushioning according to claim 1, wherein the layer has at least one orifice for the passage of a return means of the cap.

7. The cushioning according to claim 1, wherein the layer comprises a plurality of electric circuits mounted in parallel, the circuits occupying, when the layer is seen from the front, two separate zones of the cushioning.

8. The cushioning according to claim 7, wherein the cushioning is intended to form seating, the cushioning having a first front zone and a second rear zone each receiving a respective front and rear circuit.

9. A motor vehicle seat comprising a cushioning according to claim 1, the cap of the cushioning being fixed by the peripheral fastening means of the cushioning to reciprocal means outside of the cushioning provided on the seat.

10. A safety unit comprising: a seat according to claim 9, a generator connected to the electric circuit, a device for measuring the electrical resistance of the circuit, or the sub-circuits of the circuit, under the effect of a pressure produced by an occupant on the cushioning, a safety system, a device for analysing the variation(s) in the resistance(s), the device being arranged so as to activate the safety system when predetermined activation conditions are fulfilled.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0032] Other particularities and advantages of the invention will appear in the following description, made in reference to the appended figures, wherein:

[0033] FIG. 1 is a schematic, partial, cross-sectional view of a cushioning according to one embodiment, the cushioning being mounted on a seat frame,

[0034] FIG. 2 is a schematic, front view of a layer according to one embodiment,

[0035] FIG. 3 is a schematic representation of a conductive ink.

DETAILED DESCRIPTION

[0036] In reference to the figures, a cushioning 1 is described in particular for seating or backrest for a motor vehicle seat, the cushioning comprising: [0037] a padded cushion 2 made from foamin particular polyurethaneelastically compressible, [0038] a flexible layer 3 for detecting the presence of an occupant in the seat, the layer being arranged on the cushion on a face for receiving the occupant, the layer being made from a sheet 9 on which is printedin particular by screen printingan electric circuit 10 made from conductive ink, the ink being made from conductive particles 11for example, metalembedded in an elastically insulating binder 12for example, made from polyurethanethe circuit being intended to be supplied by a generator, [0039] a cap 4 covering the cushion, the cap being mounted on the cushion covering the layer, the cap being provided with return means 5in this case, in the form of hooksfastened on reciprocal means 6 secured to the cushionin this case, being formed by fastening zones provided on a metal wire shaped by folding and overmoulded by the foam on the underside of the cushionand peripheral fastening means 7in this case, in the form of stitched profiles at the periphery of the cap, the profile having a hook-shaped profileintended to cooperate with reciprocal means 8 outside of the cushioning provided on the seatthe external reciprocal means in this case being in the form of strips coming from the frame of the seat,

[0040] the cushioning furthermore having the following characteristics: [0041] the sheet is elastically stretchable, [0042] the layer is firstly separate from the cap and secondly glued, at least partially, by the underside of the sheet, to the cushion, to stretch when the cushion is deformed upon receiving an occupant, and to consequently stretch the circuit in such a way as to increase the electrical resistance of same.

[0043] It must be noted that the cap 4 being provided with return means 5 fastened on reciprocal means 6 secured to the cushion 2 and peripheral fastening means 7, this implies that the cap is not glued to the cushion.

[0044] According to one embodiment, the underside 13 of the sheet 9 is glued at least by one portion of the periphery thereof, along two opposite edges, on the cushion 2.

[0045] As an example, in the case of an electric circuit 10 comprising a filament network 14 extending transversally, as illustrated in FIG. 2, a gluing of the layer 3 by the lateral edges thereof on the cushion 2 can be provided, to observe the transversal stretching thereof when the cushioning 1 receives an occupant.

[0046] According to one embodiment variant, the underside 13 of the sheet 9 is glued totally on the cushion 2.

[0047] Such an arrangement can prove to be relevant when the electric circuit 10 has filaments 14 extending along multiple directions.

[0048] According to one embodiment, the sheet 9 is elastically stretchable in at least one direction of at least 5% with respect to the dimension thereof along the direction when it is not stretched.

[0049] According to one embodiment, the sheet 9 is made from textile, for example in the form of mesh.

[0050] It will be noted, that the sheet 9 must, of course, not have ink absorption properties during the deposition thereofthis by blotting effecton penalty of not being able to produce the expected electric circuit 10.

[0051] According to the embodiment represented, the layer 3 has at least one orifice 15 for the passage of a return means 5 of the cap 4.

[0052] According to an embodiment not represented, the layer 3 comprises a plurality of electric circuits 10 mounted parallel, the circuits occupying, when the layer is seen from the fronti.e. from high in the case of a seating cushioning or from front in the case of a backrest cushioningtwo separate zones of the cushioning 1.

[0053] According to one embodiment, the cushioning 1 is intended to form seating, the cushioning having a first front zone and a second rear zone, each receiving a respective front and rear circuit 10.

[0054] Such an arrangement can, in particular, make it possible to detect an increase in resistance of the front circuit 10 without increasing corresponding resistance for the rear circuit 10, indicating that the occupant of the cushioning 1 is too advanced towards the front to enable an airbag triggering likely to impact it.

[0055] Now, in a manner not represented, a motor vehicle seat comprising such a cushioning 1 is described, the cap 4 of the cushioning being fixed by the peripheral fastening means 7 thereofin particular in the form of stitched profiles at the periphery of the cap, the profile having a hook-shaped profilewith reciprocal means 8 outside of the cushioning provided on the seatthe external reciprocal means being in particular in the form of strips coming from the frame of the seat.

[0056] Finally, in a manner not represented, a safety unit is described, comprising: [0057] a seat such as described above, [0058] a generator connected to the electric circuit 10, [0059] a device for measuring the electrical resistance of the circuit, or of the sub-circuits thereof, under the effect of a pressure produced by an occupant on the cushioning 1, [0060] a safety system, for example in the form of a warning light in case of seatbelt not fastened or also of an airbag, [0061] a device for analysing the variation(s) in the resistance(s), the device being arranged to activate the safety system when predetermined activation conditions are fulfilled.

[0062] The analysis device can in particular be configured to detect the presence of an occupant on the cushioning 1, to activate, if necessary, a light detecting a non-fastening of their seatbelt, or also the triggering of an airbag in case of impact of the vehicle.

[0063] According to a more developed mode, the analysis device can analyse the position of the occupant on the cushioning 1, for example to obstruct, as stated above, the triggering of an airbag if the occupant is sat in a position that it too far forward on a seating cushioning 1.