SAFETY DEVICE THAT INCLUDES AT LEAST ONE SIDE AIRBAG

Description

DOMAINE TECHNIQUE DE L'INVENTION

[0001] The present invention relates generally to the safety of vehicle passengers, and in particular of automobile passengers (cars, trucks, vans, etc.).

[0002] It relates more particularly to a device for restraining an occupant of a vehicle seat, comprising an airbag (better known by the English term "airbag") which is adapted to be housed in the seat and which, when it inflates, is adapted to deploy on one side of the occupant, this airbag delimiting two separate chambers adapted to communicate with each other.

[0003] It also concerns a seat equipped with such a restraint device. STATE OF THE ART

[0004] Legislation requires the installation of airbags in the passenger compartment of a motor vehicle to reduce the damage caused to passengers in the event of an accident.

[0005] For example, document US8469395 discloses a seat equipped, in one of the two sides of its backrest, with a two-part airbag.

[0006] These two parts are designed to inflate in the event of a side impact so that they deploy respectively on the side of the seat occupant's trunk and on the side of his head.

[0007] A communication channel is provided between these two parts to allow a gas-generating cartridge to simultaneously inflate both parts of the airbag. US5575497A, the state of the art closest to the subject of claim 1, discloses a device for restraining an occupant of a vehicle seat, comprising at least one airbag which is adapted to be housed in the seat and which, when inflated, is adapted to deploy on one side of the occupant, this airbag delimiting two separate chambers adapted to communicate with each other, of which a membrane is provided which isolates the two chambers and which is adapted to yield when the pressure difference between the two chambers exceeds a threshold.

[0008] The disadvantage of such an airbag is that its shape does not allow for the desired level of safety, unless both parts have very large volumes. However, such a volume is not possible when using a single gas cartridge to inflate both parts of the airbag, since this would require too long an inflation time. PRESENTATION OF THE INVENTION

[0009] In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes an airbag whose shape ensures a good level of protection for the occupant, and whose structure allows it to be put in place quickly, in the desired position, preferably using a single gas-generating cartridge.

[0010] More particularly, the invention provides a restraint device as defined in the introduction, in which the airbag is shaped so that, when it inflates, it passes under an armpit of the occupant and rises up the side of the occupant's head, and in which a membrane is provided which isolates the two chambers of the cushion and which is adapted to yield when the pressure difference between the two chambers exceeds a threshold.

[0011] Thus, thanks to its shape, the airbag passes along the side of the seat occupant's trunk and rises towards their head, which ensures good protection for the occupant in the event of a side impact. Due to its particular "curved sausage" shape, it is necessary that the airbag is correctly positioned in the vehicle.

[0012] If it were without a membrane, this installation would not always be successful. Thanks to the membrane, the first chamber of the airbag can fully inflate before the second chamber inflates, which ensures proper positioning of the first chamber and, therefore, of the second chamber.

[0013] In other words, the inflation of the two chambers, not simultaneously but successively, ensures the correct positioning of the airbag when it is deployed.

[0014] Other advantageous and non-limiting characteristics of the retaining device according to the invention, taken individually or in all technically possible combinations, are the following: the membrane completely isolates the two chambers; the first chamber forms a loop; the second chamber extends substantially along a diameter of said loop; the membrane is made of a material distinct from that of the rest of the airbag, which is adapted to tear when the pressure difference between the two chambers exceeds said threshold; the membrane is made of a material identical to that of the rest of the airbag; the membrane is fixed to the rest of the airbag by fixing means adapted to yield when the pressure difference between the two chambers exceeds said threshold; the fixing means comprise a seam adapted to yield when the pressure difference between the two chambers exceeds said threshold; the fixing means comprise an adhesive adapted to yield when the pressure difference between the two chambers exceeds said threshold;there is provided a further airbag adapted to deploy on the other side of the occupant, the two airbags being substantially symmetrical to each other. ;

[0015] The invention also relates to a vehicle seat, comprising a seat and a backrest which comprises a retaining device as mentioned above.

[0016] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0017] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0018] On the attached drawings: [ Fig. 1 ] is a schematic side view of a motor vehicle, showing a seat, an occupant of this seat and a safety device in accordance with the invention; [ Fig. 2 ] is a schematic front view of the seat, occupant and safety device of the figure 1 ; [ Fig. 3 ] is a schematic side view of the safety device of the figure 1 .

[0019] On the figure 1 , a seat 30 occupied by one person has been represented.

[0020] This seat 30 is installed here in the passenger compartment of a car. Alternatively, it could be installed in the passenger compartment of any other type of vehicle (truck, wagon, etc.).

[0021] This is the seat 30 of the driver 20 of this vehicle 40. Of course, it could alternatively be another of the vehicle's seats.

[0022] This seat conventionally comprises a seat 31 and a backrest 32 equipped with a headrest. The backrest 32 has a central support portion for the driver's back 20, and two sides located on either side of this central portion, placed on each side of the driver's trunk when the latter is seated in a centered position on the seat 30.

[0023] The seat 30 is here equipped with a device 10 for restraining the driver 20 in the event of a side impact, that is to say a device for restraining the driver and absorbing the shock felt when the car hits an obstacle from the side or when it is itself hit from the side (left or right).

[0024] In the remainder of the description, the terms “lower” (or “bottom”) and “upper” (or “top”), “front”, “rear”, “right” and “left” will be used in relation to the seat 30 of the motor vehicle 40, the lower side of an element designating for example the part of this element which is turned towards the floor of the vehicle.

[0025] As shown in the figure 2 , the restraint device 10 comprises two safety airbags, hereinafter more simply called airbags 100.

[0026] These two cushions 100 are located on either side of the driver 20. These two cushions 100 being similar (more precisely symmetrical to each other with respect to the median plane of the seat), only one of them will be described in the remainder of this presentation (namely the left cushion).

[0027] As shown in the figure 1 , this cushion 100 is equipped with a single gas generating cartridge 11 allowing it to be inflated in the event of an accident.

[0028] It is fully housed in the seat 30 as long as no shock has been felt and the gas-generating cartridge 11 has not been triggered. In this position, the cushion 100 is more precisely housed in a pocket 12 located in one of the sides of the backrest 32, being folded into it.

[0029] In the remainder of the description, this cushion 100 will be described in the inflated and deployed state. It is also shown in the various figures in this state.

[0030] As the figures 1 And 3 , the cushion 100, which is deployed on the left side of the driver 20, delimits two chambers 110, 120.

[0031] Each of these two chambers 110, 120 is delimited by a fabric envelope 111, 121, which is distinct from that of the other chamber.

[0032] The first envelope 111, which delimits the first of these chambers 110, here forms a curved sausage while the second envelope 121, which delimits the second chamber 120, forms a straight sausage.

[0033] The first envelope 111 extends here from the left side of the backrest 32. It therefore has an end attached to this side, at the level of which there is an opening through which the gas from the cartridge is blown.

[0034] This first envelope has, on the side of this end, a first part in the shape of an inverted S, which extends over a second part in order to form a loop 113. The first envelope 111 therefore forms a half-loop 112 (corresponding to the lower part of this S) which allows it to pass under the armpit of the arm 21, from the left side of the backrest, and to rise above the shoulder of the driver 20.

[0035] This half-loop 112 then extends upwards and is curved forwards so as to form the loop 113.

[0036] This loop 113 is complete (i.e. “closed) since the second end of the first envelope 111 rests against the half-loop 112.

[0037] The first envelope 111 therefore extends generally along a plane parallel to the median plane of the seat 30, on the side of the driver 20. Its loop 113 is placed in particular on the side of the head 22 of the driver 20. The upper part of this loop extends to the height of the top of the driver's head.

[0038] It will be noted, with reference to the figure 2 , that the first envelope 111 has a width much smaller at the level of the half-loop 112 than at the level of the loop 113, so as not to force the driver to spread his arms.

[0039] As shown in the figure 3 , the second envelope 121, which delimits the second chamber 120, extends generally along a diameter of the loop 113, at the height of the driver's neck. It has a maximum width greater than the maximum width of the first envelope 111 (see figure 2 ).

[0040] It extends here substantially horizontally. In the event that the vehicle is struck from the side, it allows the neck of the driver 20 to be held, the head of which is held by the first envelope 111.

[0041] This second envelope 121 is attached only by its front end to the first envelope 111. Its other end is free and it comes to bear against the first envelope 111.

[0042] The two rooms 110, 120 are quite distinct but adapted to communicate with each other.

[0043] For this, the second envelope 121 is opened on the side of its front end and it is sewn on the edge of an opening provided in the first envelope 111.

[0044] In the context of the invention, a membrane 125 is provided to isolate the two chambers 110, 120, which is adapted to yield when the pressure difference between the two chambers 110, 120 exceeds a threshold. The idea is that this membrane 125 allows the first chamber 110 to inflate completely and position itself correctly in the passenger compartment of the vehicle before the second chamber 120 inflates.

[0045] It will be noted that the pressure threshold beyond which the membrane 125 will yield to allow the second chamber 120 to inflate will preferably be at least two times lower than the pressure necessary to cause the fabric envelopes 111, 121 to yield. It will even more preferably be lower than the maximum pressure which will be reached in the two chambers 110, 120 when the entire gas-emitting cartridge 11 has been consumed.

[0046] Preferably, this membrane 125 completely isolates the two chambers 110, 120, so that only the first chamber 110 inflates until the membrane 125 has given way under pressure.

[0047] Alternatively, it could be provided that the membrane 125 only globally isolates the two chambers, tolerating leaks between the two chambers representing a maximum of 5 to 15% of the air volume.

[0048] Regardless, the membrane 125 allows the first chamber 110 to fully inflate to its deployed position in the vehicle before the second chamber 120 begins to deploy.

[0049] Several embodiments of the membrane 125 can be envisaged, and in particular the following three.

[0050] In a first embodiment, the membrane 125 is made of a material which is different from that used to make the envelopes 111, 121 and which is adapted to tear when the pressure difference between the two chambers 110, 120 exceeds the expected threshold.

[0051] The membrane can then be glued or, preferably, sewn onto the envelopes, or even fixed to them in various other ways.

[0052] For example, the membrane 125 can be made of rubber.

[0053] In another example, it can be made from a fabric whose yarn and weave have a known breaking strength at least twice as low as that of the fabric used to make the envelopes 111, 121.

[0054] In a second embodiment, the membrane 125 is made of a material identical to that of the envelopes 111, 121. In this embodiment, the membrane 125 is then fixed to the envelopes 111, 121 by fixing means adapted to yield when the pressure difference between the two chambers 110, 120 exceeds the expected threshold.

[0055] For example, the membrane 125 can be sewn onto one or other of the envelopes using a thread having a known breaking strength, which strength is at least two times lower than the strength of the thread used to sew the two envelopes 111, 121 onto each other.

[0056] Alternatively, the membrane 125 may be bonded to either of the envelopes using an adhesive having a known breaking strength.

[0057] In a third embodiment, the membrane 125 is made of a material distinct from that of the envelopes 111, 121, which is adapted to tear when the pressure difference between the two chambers 110, 120 exceeds the intended threshold, and the membrane 125 is fixed to the envelopes 111, 121 by fixing means adapted to yield when the pressure difference between the two chambers 110, 120 exceeds this threshold.

[0058] This third embodiment provides redundancy that ensures membrane rupture when the first chamber is fully inflated and deployed in the proper position.

[0059] As the figure 3 , the space delimited internally by the loop 113 formed by the first envelope 111 is preferably entirely closed, on the one hand by the second envelope 121, and on the other hand by two sails 131, 132 which extend on either side of the second envelope 121. These two sails make it possible to ensure that the cushion 100 takes the desired shape when it is inflated.

[0060] The two sails 131, 132 may each be formed from a single sheet of fabric or from strips separated from each other. They may be sewn onto the edges of the envelopes. They differ from these envelopes in that they are not inflatable. Here, they are formed from a single thickness of fabric. On the figure 1 , the sails were hatched to distinguish them from the two envelopes and to allow the driver's head to appear transparent.

[0061] It will be noted that in all embodiments, the cushion 100 will not have a strap to hold it relative to the seat in order to ensure its deployment in the desired position. Only one of the ends of the first envelope 111 is in fact attached to the seat.

[0062] The present invention is in no way limited to the embodiment described and shown, but those skilled in the art will be able to provide any variation in accordance with the invention.

[0063] For example, the seat could be equipped with only one cushion of the type shown in the figure 2 , in which case this cushion will preferably be placed between the driver and his door.

Claims

1. Device (10) for restraining an occupant (20) of a seat (30) of a vehicle (40), comprising at least one airbag (100) that is designed to be housed in the seat (30) and that, when it inflates, is designed to deploy on one side of the occupant (20), this airbag (100) delimiting two distinct chambers (110, 120) that are designed to communicate with one another, characterized in that the airbag (100) is shaped so as to, when it inflates, pass beneath an armpit of the occupant (20) and rise up on the side of the head (22) of the occupant (20), and in that a membrane (125) is provided that isolates the two chambers (110, 120) and that is designed to yield when the pressure difference between the two chambers (110, 120) exceeds a threshold.

2. Restraining device (10) according to the preceding claim, wherein the membrane (125) completely isolates the two chambers (110, 120).

3. Restraining device (10) according to either of Claims 1 and 2, wherein the first chamber (110) forms a loop.

4. Restraining device (10) according to Claim 3, wherein the second chamber (120) extends substantially along a diameter of said loop.

5. Restraining device (10) according to one of Claims 1 to 4, wherein the membrane (125) is made of a material distinct from that of the rest of the airbag (100), which is designed to tear when the pressure difference between the two chambers (110, 120) exceeds said threshold.

6. Restraining device (10) according to one of Claims 1 to 4, wherein the membrane (125) is made of a material identical to that of the rest of the airbag (100), and wherein the membrane (125) is fastened to the rest of the airbag (100) by fastening means that are designed to yield when the pressure difference between the two chambers (110, 120) exceeds said threshold.

7. Restraining device (10) according to Claim 6, wherein the fastening means have a seam that is designed to yield when the pressure difference between the two chambers (110, 120) exceeds said threshold.

8. Restraining device (10) according to Claim 6, wherein the fastening means have an adhesive that is designed to yield when the pressure difference between the two chambers (110, 120) exceeds said threshold.

9. Restraining device (10) according to one of Claims 1 to 8, wherein another airbag (100) is provided that is designed to deploy on the other side of the occupant (20), the two airbags (100) being substantially symmetrical to one another.

10. Seat (30) for a vehicle, having a seat pan (31) and a backrest (32), characterized in that the backrest (32) has a restraining device (10) in accordance with one of Claims 1 to 9.