Safety device

Abstract

A safety device (1) for a vehicle seat, the safety device (1) comprising an air-bag (2) configured to be mounted in a squab (14) of a vehicle seat over part of a frame of the vehicle seat (11), a portion of the air-bag (2) having a first stiffness and an air-bag force distribution member (12) coupled to the air-bag (2), such that upon inflation of the air-bag (2) the air-bag force distribution member (12) distributes a force imparted by the air-bag (2) on the part of the frame of the vehicle seat (11), wherein the air-bag force distribution member (12) has a second stiffness that is greater than the first stiffness.

Description

[0001] SAFETY DEVICE

[0002] FIELD

[0003] The present invention relates to a safety device for a vehicle seat. The present invention more particularly relates to a safety device comprising an air-bag to be mounted within a squab of a vehicle seat.

[0004] BACKGROUND

[0005] When a motor vehicle experiences a frontal impact, an occupant of the vehicle is at risk of an effect known as “submarining”. Submarining occurs when the occupant sitting in a vehicle seat is not properly restrained by a seat belt and sinks into the seat during impact. The occupant may then slide under a lap belt of the seat belt and sustain more severe injuries than if the occupant remained secured in the seat.

[0006] A pelvic restraint cushion (PRC) is an inflatable air-bag mounted within a squab of a vehicle seat. When a vehicle safety system detects a crash situation, the safety system activates the PRC causing it to inflate. When mounted to a sufficiently rigid surface, the inflated PRC pushes the occupant up and into the seat belt, to properly restrain the occupant. This minimises the risk of the occupant sinking into the seat and submarining.

[0007] Vehicle seats comprise a seat frame which is made of a stiff material and generally provides a sufficiently rigid surface for a PRC push against when inflating. However, to facilitate passenger comfort, seat frames often comprise a wire frame portion. The wire frame section is significantly less rigid than a solid portion of the seat frame. Therefore, when a PRC inflates and pushes against the wire frame section of a seat frame, the PRC does not perform optimally. This can compromise the PRC restraining function and result in the occupant submarining during an impact, despite the presence of the PRC.

[0008] Vehicle seats also often comprise a pressure sensor for use with an occupant classification system (OCS). The pressure sensor is typically positioned above a PRC within a squab of a vehicle seat. The pressure sensor detects whether an occupant is sitting on the seat and may also measure the force the occupant’s weight is imparting on the seat. A problem can occur when a pressure sensor is positioned above a PRC air-bag because the pressure sensor is pressed against the uninflated PRC air-bag when an occupant is sitting on the seat, which can cause an upper surface of the uninflated PRC air-bag to deform away from the pressure sensor. This can lead to suboptimal pressure sensor readings. There is a need for a safety device for a vehicle seat that alleviates at least some of the problems outlined herein.

[0009] BRIEF DESCRIPTION OF THE INVENTION

[0010] The present invention provides a safety device for a vehicle seat as claimed in claims 1 and 6. The present invention also provides methods of manufacturing a safety device, as claimed in claims 1 1 -13. The present invention also provides preferred embodiments as claimed in the dependent claims.

[0011] BRIEF DESCRIPTION OF THE FIGURES

[0012] In order that the present disclosure may be more readily understood, preferable embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0013] Figure 1 is a diagrammatic isometric view from below of a safety device of an example of this disclosure, Figure 2 is a diagrammatic isometric view from above of the safety device of Figure 1 ,

[0014] Figure 3 is a diagrammatic cross-sectional view of part of a squab of a vehicle seat comprising the safety device of an example of this disclosure,

[0015] Figure 4 is a diagrammatic cross-sectional view of a safety device of an example of this disclosure installed on a seat frame,

[0016] Figure 5 is a view corresponding to Figure 4 during activation of the safety device,

[0017] Figure 6 is a view corresponding to Figure 4 during activation of the safety device, and

[0018] Figure 7 is a diagrammatic cross-sectional view of a safety device of an example of this disclosure installed within a squab of a vehicle seat.

[0019] DETAILED DESCRIPTION OF THE DISCLOSURE

[0020] Referring initially to Figures 1 to 3 of the accompanying drawings, a safety device 1 of examples of this disclosure comprises an air-bag 2 which is configured to be mounted within a squab of a vehicle seat. In this example, the air-bag 2 is a pelvic restraint cushion (PRC).

[0021] The air-bag 2 is of a deformable material. The air-bag 2 of this example of the disclosure comprises a first layer 3 superimposed on a second layer 4. In this example, the first layer 3 and second layer 4 are of fabric. The first layer 3 and second layer 4 are connected at least partially around their perimeter by a seam 5, to form an air-bag chamber 6 between the first layer 3 and second layer 4. In other examples, the seam 5 is omitted and the air-bag 2 is instead formed by one-piece weaving. The air-bag comprises an inlet aperture through which compressed gas may enter the air-bag chamber 6 to inflate the air-bag 2. When uninflated, the layers 3, 4 of the air-bag 2 have a first stiffness. In this example, the layers 3, 4 are of a fabric which is soft and flexible when the air-bag is uninflated. The air-bag 2 comprises a first portion 7 and a second portion 8. In this example, the first portion 7 is provided with a cutaway section 9 and the second portion 8 has a generally rectangular profile. In this example, the cutaway section 9 is generally U-shaped. In other examples, the cutaway section 9 is a different shape or the cutaway section 9 is omitted.

[0022] The air-bag 2 of this example of the disclosure further comprises at least one optional attachment formation 10 for attaching the air-bag 2 to a vehicle seat frame 1 1 . In this example, each attachment formation 10 comprises a respective bolt hole, which aligns with a corresponding bolt hole in the vehicle seat frame 1 1 .

[0023] In use, the air-bag 2 is fluidly coupled to an inflator via the inlet aperture so that upon activation, the inflator injects a gas into the air-bag chamber 6 to inflate the air-bag 2.

[0024] The air-bag 2 comprises an air-bag force distribution member 12 which is attached to the air-bag 2. In this example, the attachment is a sewn thread. In other examples, the attachment is an adhesive attachment. In this example, the air-bag force distribution member 12 comprises a planar or substantially planar body 13. In this example, the air-bag force distribution member 12 is superimposed on the first portion 7 of the air-bag 2. In other examples, the air-bag force distribution member 12 comprises a plurality of planar bodies 13 which are superimposed on separate parts of the first portion 7 of the air-bag 2.

[0025] When the safety device 1 is in use, the safety device 1 is positioned within a vehicle seat squab 14, as shown in Figure 3. When the air-bag 2 is mounted to the vehicle seat frame 1 1 , the air-bag force distribution member 12 is positioned between the air-bag 2 and vehicle seat frame 1 1 . In this example the planar body 13 comprises an angled portion 15 which follows a contour of the vehicle seat frame 1 1 .

[0026] The air-bag force distribution member 12 has a second stiffness which is greater than the first stiffness of the layers 3, 4 of the air-bag 2. In some examples, the air-bag force distribution member 12 is of a rigid material. In some examples of the disclosure, the air-bag force distribution member 12 is of a self- supporting material. In some examples, the air-bag force distribution member 12 is of a substantially isotropic material. In this example the air-bag force distribution member 12 is of plastic. In other examples, the air-bag force distribution member 12 is of metal. The air-bag force distribution member 12 is preferably of a different material to the layers 3, 4 of the air-bag 2. In this example the thickness of the air-bag force distribution member 12 is at least 2 mm.

[0027] Referring now to Figure 4 of the accompanying drawings, when installed and uninflated, the air-bag 2 is mounted to the vehicle seat frame 1 1 . The air-bag force distribution member 12 is positioned between the air-bag 2 and the vehicle seat frame 1 1 . The air-bag 2 follows the contour of the vehicle seat frame 1 1 such that an inflation cavity 16 is formed. Referring now to Figure 5 of the accompanying drawings, upon activation, the inflator provides pressurised gas to the air-bag chamber 6 through the inlet aperture. This causes the volume of the airbag chamber 6 to rapidly increase, thereby inflating the air-bag 2. During inflation, the air-bag 2 expands to fill the inflation cavity 16.

[0028] Referring now to Figure 6 of the accompanying drawings, the inflating air-bag 2 exerts an outward force in all directions and hence pushes against the air-bag force distribution member 12. The air-bag force distribution member 12 exerts a reaction force on the expanding air-bag 2 and minimises or prevents the expansion of the air-bag 2 through a wire frame section of the vehicle seat frame 1 1 . This reaction force causes the air-bag 2 to expand further in the direction of the top of the vehicle seat squab 14. The air-bag 2 is thus configured to inflate optimally in a direction towards an occupant sitting on the vehicle seat squab 14. The air-bag 2 therefore restrains the occupant against a vehicle seat belt and minimises the risk of the occupant “submarining” by sliding under a lap belt of the seat belt during a crash situation.

[0029] Referring again to Figures 2 and 3 of the accompanying drawings, in this example the air-bag 2 comprises a sensor force distribution member 17 which is attached to a side of the air-bag 2 which is opposite to the air-bag force distribution member 12. In use, the air-bag 2 is oriented such that the sensor force distribution member 17 is positioned on the upper side of the air-bag 2 and the air-bag force distribution member is positioned on the lower side of the air-bag 2. The sensor force distribution member 17 of this example comprises a further planar or substantially planar body 18. In this example, the further planar body 18 is at least partly superimposed on the second portion 8 of the air-bag 2.

[0030] The sensor force distribution member 17 is attached to the air-bag 2. In this example, the attachment is a sewn thread. In other examples, the attachment is an adhesive attachment.

[0031] Referring now to Figure 7 of the accompanying drawings, when the air-bag 2 is installed within the squab 14 of a vehicle seat, the sensor force distribution member 17 is positioned between the air-bag 2 and a pressure sensor 19. The pressure sensor 19 is typically a flat silicone component. In this example, when the air-bag 2 is uninflated, the inflation cavity 16 exists between the air-bag 2 and the sensor force distribution member 17, where a portion of the air-bag 2 is not in physical contact with the sensor force distribution member 17.

[0032] The sensor force distribution member 17 has a third stiffness which is greater than the first stiffness of the layers 3, 4 of the air-bag 2. In some examples, the sensor force distribution member 17 is of a rigid material. In some examples of the disclosure, the sensor force distribution member 17 is of a self- supporting material. In some examples, the sensor force distribution member 17 is of a substantially isotropic material. In this example the sensor force distribution member 17 is of plastic. In other examples, the sensor force distribution member 17 is of metal. The sensor force distribution member 17 is preferably of a different material to the layers 3, 4 of the air-bag 2. In this example the thickness of the sensor force distribution member 17 is at least 2 mm.

[0033] The effect of the sensor force distribution member 17 when an occupant is seated on the vehicle seat squab 14, in a normal operating situation, will now be discussed with reference to Figure 7 of the accompanying drawings. When an occupant is seated on the vehicle seat squab 14, the occupant exerts a force, indicated generally by arrow 20, on the vehicle seat squab 14, which in turn exerts a force on the pressure sensor 19. The pressure sensor 19 imparts a force against the sensor force distribution member 17 which distributes this force across part of the upper surface uninflated air-bag 2. Consequently, the sensor force distribution member 17 provides a rigid and stable support for the pressure sensor 19 to press against. This support optimises operation of pressure sensor 19 and ensures that an occupant classification system can function correctly.

[0034] While in the examples described above, the safety device 1 comprises both the air-bag force distribution member 12 and the sensor force distribution member 17, in other examples one or other of the air-bag force distribution member 12 or the sensor force distribution member 17 is omitted.

[0035] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0036] The invention may also broadly consist in the parts, elements, steps, examples and / or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and / or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

[0037] Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

[0038] Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and / or to encompass equivalents. REPRESENTATIVE FEATURES

[0039] Representative features are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and / or drawings of the specification.

[0040] Clause 1 : A safety device for a vehicle seat, the safety device comprising: an air-bag configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat, a portion of the air-bag having a first stiffness; and an air-bag force distribution member coupled to the air-bag, such that upon inflation of the air-bag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a second stiffness that is greater than the first stiffness.

[0041] Clause 2: The safety device of clause 1 , wherein the air-bag force distribution member comprises at least one substantially planar body.

[0042] Clause 3: The safety device of any one of the preceding clauses, wherein the air-bag force distribution member is at least partly of plastic.

[0043] Clause 4: The safety device of any one of the preceding clauses, wherein the air-bag force distribution member is configured to limit expansion of the air-bag in at least one direction during inflation of the air-bag.

[0044] Clause 5: The safety device of any one of the preceding clauses, wherein the safety device further comprises a sensor force distribution member coupled to the air-bag, wherein the sensor force distribution member has a third stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

[0045] Clause 6: A safety device for a vehicle seat comprising: an air-bag configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat, a portion of the air-bag having a first stiffness; and a sensor force distribution member coupled to the air-bag, wherein the sensor force distribution member has a second stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

[0046] Clause 7: The safety device of clause 6, wherein the sensor force distribution member comprises a substantially planar body. Clause 8: The safety device of any one of clauses 6 or 7, wherein the sensor force distribution member is at least partly of plastic.

[0047] Clause 9: The safety device of any one of clauses 6 to 8 comprising a recess between the air-bag and the sensor force distribution member, wherein when the air-bag inflates it expands to at least partly fill the recess.

[0048] Clause 10: The safety device of any one of clauses 6 to 9, wherein the safety device further comprises an air-bag force distribution member coupled to the air-bag, such that upon inflation of the air-bag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a third stiffness that is greater than the first stiffness.

[0049] Clause 1 1 : A method of manufacturing a safety device, the method comprising: providing an air-bag which is configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat; and coupling an air-bag force distribution member to the air-bag, such that upon inflation of the air-bag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a second stiffness that is greater than the first stiffness.

[0050] Clause 12: A method of manufacturing a safety device, the method comprising: providing an air-bag which is configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat, a portion of the air-bag having a first stiffness; and coupling a sensor force distribution member to the air-bag, wherein the sensor force distribution member has a second stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

[0051] Clause 13: A method of manufacturing a safety device, the method comprising: providing an air-bag which is configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat; coupling an air-bag force distribution member to the air-bag, such that upon inflation of the air-bag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a second stiffness that is greater than the first stiffness; and coupling a sensor force distribution member to the air-bag, wherein the sensor force distribution member has a third stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

Claims

CLAIMS1 . A safety device for a vehicle seat, the safety device comprising: an air-bag configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat, a portion of the air-bag having a first stiffness; and an air-bag force distribution member coupled to the air-bag, such that upon inflation of the airbag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a second stiffness that is greater than the first stiffness.

2. The safety device of claim 1 , wherein the air-bag force distribution member comprises at least one substantially planar body.

3. The safety device of any one of the preceding claims, wherein the air-bag force distribution member is at least partly of plastic.

4. The safety device of any one of the preceding claims, wherein the air-bag force distribution member is configured to limit expansion of the air-bag in at least one direction during inflation of the airbag.

5. The safety device of any one of the preceding claims, wherein the safety device further comprises a sensor force distribution member coupled to the air-bag, wherein the sensor force distribution member has a third stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

6. A safety device for a vehicle seat comprising: an air-bag configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat, a portion of the air-bag having a first stiffness; and a sensor force distribution member coupled to the air-bag, wherein the sensor force distribution member has a second stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

7. The safety device of claim 6, wherein the sensor force distribution member comprises a substantially planar body.

8. The safety device of any one of claims 6 or 7, wherein the sensor force distribution member is at least partly of plastic.

9. The safety device of any one of claims 6 to 8 comprising a recess between the air-bag and the sensor force distribution member, wherein when the air-bag inflates it expands to at least partly fill the recess.

10. The safety device of any one of claims 6 to 9, wherein the safety device further comprises an air-bag force distribution member coupled to the air-bag, such that upon inflation of the air-bag the airbag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a third stiffness that is greater than the first stiffness.1 1 . A method of manufacturing a safety device, the method comprising: providing an air-bag which is configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat; and coupling an air-bag force distribution member to the air-bag, such that upon inflation of the airbag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a second stiffness that is greater than the first stiffness.

12. A method of manufacturing a safety device, the method comprising: providing an air-bag which is configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat, a portion of the air-bag having a first stiffness; and coupling a sensor force distribution member to the air-bag, wherein the sensor force distribution member has a second stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

13. A method of manufacturing a safety device, the method comprising: providing an air-bag which is configured to be mounted in a squab of a vehicle seat over part of a frame of the vehicle seat; coupling an air-bag force distribution member to the air-bag, such that upon inflation of the airbag the air-bag force distribution member distributes a force imparted by the air-bag on the part of the frame of the vehicle seat, wherein the air-bag force distribution member has a second stiffness that is greater than the first stiffness; and coupling a sensor force distribution member to the air-bag, wherein the sensor force distribution member has a third stiffness that is greater than the first stiffness, such that the sensor force distribution member distributes a force imparted by a pressure sensor in the squab of the vehicle seat when an occupant is seated on the squab of the vehicle seat.

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