WO2012105957A1

WO2012105957A1 - Vehicle seat assembly with air bag guide having attachment tabs

Info

Publication number: WO2012105957A1
Application number: PCT/US2011/023303
Authority: WO
Inventors: Michael Tracht; Karsten Mueller
Original assignee: Lear Corporation
Priority date: 2011-02-01
Filing date: 2011-02-01
Publication date: 2012-08-09

Abstract

In at least certain embodiments, the vehicle seat assembly comprises a frame, a seat pad, a trim cover extending over the seat pad and including a release seam adjacent the seat pad, and an air bag assembly within the trim cover. In accordance with this embodiment, the air bag assembly includes an inflator and an air bag inflatable to project outwardly from the seat through the air bag release seam of the trim cover. Further in accordance with this embodiment, the vehicle seat assembly further includes an air bag guide including an inner panel and an outer panel that are associated with the air bag assembly and each having a plurality of tabs connected to the trim cover.

Description

VEHICLE SEAT ASSEMBLY WITH AIR BAG

GUIDE HAVING ATTACHMENT TABS

TECHNICAL FIELD

The present invention relates to a vehicle seat assembly, and particular, a seat assembly including an air bag.

BACKGROUND

Vehicles can be equipped with side air bags, which may be in the form of an air bag disposed within a vehicle seat assembly. One limitation of air bags that are located within a seat assembly, is that the air bag needs to break through the seating material before it can fully deploy to protect a vehicle occupant. During deployment, such an air bag may encounter foam, or other seat pad materials, and must then break through a seat trim cover in order to escape from the seat assembly. Another limitation is that the air bag should break through the cover material at a predetermined location to optimize effectiveness.

Prior vehicle seat assemblies equipped with side air bags and manufacturing methods are disclosed in U.S. Patent Nos. 5,816,610, 5,860,673, 5,938,232, 6,045,151, 6,237,934, 6,588,838, 7,134,685, 7,731,226, 7,543,847, 7,637,529 and 7,654,612, for example.

SUMMARY

Under the invention, a vehicle seat assembly is provided. In at least one embodiment, the vehicle seat assembly comprises a frame, a seat pad adjacent the frame, a trim cover extending over at least a part of the seat pad and having a release seam adjacent the seat pad, and an air bag assembly mounted on the frame within the trim cover in a spaced relationship from the air bag release seam. In accordance with this embodiment, the air bag assembly includes an inflator and a folded air bag that is inflatable by the inflator to unfold and project outwardly from the seat through the air bag release seam of the trim cover. Further in accordance with this embodiment, the vehicle seat assembly includes an air bag guide including an inner panel and an outer panel that are each made of flexible material and are associated with the air bag assembly, with the air bag guide having a plurality of spaced apart tabs connected to the release seam.

In at least one embodiment, the trim cover comprises a front trim panel and a side trim panel connected to each other to form the release seam, with a first plurality of the tabs being connected on the front trim panel and a second plurality of the tabs being connected to the side trim panel. In yet another embodiment, the trim cover comprises a front trim panel and a side trim panel connected to each other to form the release seam, with the tabs being connected on one side of the release seam to one of the trim panels.

In at least another embodiment, the tabs are spaced from each other in a predetermined manner to enable the force of a deploying air bag to be concentrated at a predetermined location of the release seam.

In yet at least another embodiment, the vehicle seat assembly comprises a frame, a seat pad adjacent the frame, and a trim cover extending over the seat pad that includes a front trim panel and a side trim panel cooperating to form a release seam adjacent the seat pad, with the trim panel having a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area, and an outer surface and an inner surface. In this embodiment, the seat assembly further comprises an air bag assembly within the trim cover in a spaced relationship from the release seam, with the air bag assembly including an inflator and a folded air bag that is inflatable by the inflator to unfold and project outwardly from the seat through the release seam of the trim cover. In this embodiment, the seat assembly also further comprises an air bag guide including an inner panel and an outer panel having tabs at forward ends, and rear ends connected to each other behind the air bag assembly, with the tabs being connected to the release seam in an alternating manner. In still yet at least another embodiment, a method of making a vehicle seat assembly is provided. In this embodiment, the method comprises providing a frame, mounting a seat pad on the frame, and disposing a trim cover over the seat pad, with the trim cover including a release seam adjacent the seat pad and a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area. In this embodiment, the method further comprises providing an air bag assembly adjacent the frame within the trim, with the air bag assembly including an air bag that is inflatable to project outwardly from the seat through the release seam of the trim cover, and providing an air bag guide including a first panel and a second panel of sheet material having forward ends comprising a plurality of tabs, associating the air bag guide with the air bag assembly, and connecting the tabs of the air bag guide to the release seam, with the tabs being spaced in such a manner so that, upon deployment of the air bag, one of the protection areas of the release seam will open before the other protection areas. While exemplary embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a fragmentary side view of a portion of a seat assembly in accordance with the present invention;

FIGURE 2 is a fragmentary sectional view of the seat assembly shown in Figure 1, taken through line 2-2;

FIGURE 3 is a view similar to Figure 2 showing the parts in a different position;

FIGURE 4 is a view similar to Figure 2 showing another embodiment; FIGURE 5 is a fragmentary sectional view of portions of the seat assembly shown in Figure 2;

FIGURE 6 is a perspective view of the seat assembly shown in Figure

5; FIGURE 7 is a fragmentary sectional view of components of the seat assembly shown in Figure 6 taken along line 7-7;

FIGURE 8 is similar to Figure 7 showing another embodiment; and

FIGURE 9 is a plan view of one of the components shown in Figure

1. DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various alternative forms. The figures are not necessarily of scale, some features may be exaggerated or minimized to show details of particular components. Therefore specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or a representative basis for teaching one skilled in the art to variously employ the present invention.

Moreover, except where otherwise expressly indicated, all numerical quantities in this description and in the claims indicating amounts of materials or conditions of reactions and/or use are to be understood as modified by the word "about" in describing the broader scope of this invention. Practice within the numerical limits stated is generally preferred. Also, unless expressly stated to the contrary, the description of a group or class of materials as suitable preferred for a given purpose in connection with the invention implies that mixtures of any two or more members of the group or class may be equally suitable or preferred. Figure 1 shows a portion of a seat assembly 10 in accordance with the present invention. The seat assembly 10 includes a seat back 12, and seat pad 16 covered by a trim cover 18. As is well known, the seat assembly 16 includes a seat bottom (not shown). The trim cover 18 may be made of any suitable material such as cloth, vinyl or leather, etc. As is shown in Figure 1, in at least some embodiments, a relatively rigid plastic molding 14 can optionally be provided in the rear area of the seat assembly 10 to provide support and/or for aesthetics.

In at least one embodiment, the seat pad 16 is made from a molded polymeric material, such as a polyurethane foam. The use of a polymeric foam material to construct the seat pad 16 can be cost effective and can provide the flexibility needed to easily change the shape of the seat pad for different types of seat assemblies. Of course, other types of polymeric materials may be molded to form the seat pad 16.

Disposed within the seat back 12 is an air bag assembly, such as a side air bag assembly 20. While the side air bag assembly 20 is shown on the seat back 12, which is a usage for which it has particular utility, it is also possible for the side air bag assembly to be utilized with a seat bottom even though the seat back usage is specifically disclosed. Also, as illustrated, the air bag assembly 20 is located at an outboard lateral side or extremity of the seat to provide protection against adjacent vehicle structure, but it is also possible to have the side air bag assembly located at the inboard lateral side to provide protection against an adjacent vehicle occupant and to also have side air bag assemblies at both outboard and inboard locations for protection in both lateral directions.

As shown in Figure 2, the air bag assembly 20 includes an air bag 22 and an inflator 24, which is configured to supply inflation fluid such as gas to the air bag 22, thereby facilitating deployment of the air bag 22. In at least one embodiment, the air bag assembly 20 also includes a housing 40 which at least partially surrounds the air bag 22 and the inflator 24. Also shown in Figure 2 is a portion of a seat frame 26 which can be used for mounting the seat assembly 10 to a vehicle. The seat pad 16 is disposed proximate the frame 26 and air bag assembly 20 and may be directly attached to the frame 26 at various points. The trim cover 18 includes a first or front panel 21 and a second or side panel 23 that cooperate to form an air bag release seam 28 which in at least one embodiment is adjacent to a side 30 of the seat pad 16. In at least one embodiment, the release seam 28 is 40 to 70 cm in length, but can be any suitable length. Referring to Figure 1 , the release seam 28 extends over a head protection area 29, a shoulder protection area 31 , a thorax protection area 33, and a pelvis protection area 35. These areas 29, 31 , 33 and 35 generally correspond with the respective body parts of an average sized vehicle occupant. That is that the respective deployment areas 29-35 are generally disposed adjacent the respective body parts (i.e., head, shoulder, thorax and pelvis) of an average sized vehicle occupant.

Referring again to Figure 2, the air bag assembly 20 is located within the trim cover 18 and may be conventionally mounted, such as on the frame 26, adjacent the air bag release seam 28 but in a spaced relationship from the release seam. The schematically illustrated folded air bag 22, upon deployment, is inflated by inflation fluid from the inflator 24 to unfold and project outwardly from the seat 10 through the air bag release seam 28 of the trim cover 18 (Figure 3). With continuing reference to Figure 2, an air bag guide of the seat back component is generally indicated by 32 and, in at least one embodiment, includes an inner panel 34 and an outer panel 36 that are each made of any suitable sheet material effective to protect the seat pad 16 during deployment of the air bag 22. For example, a woven or non-woven cloth material, which may include natural or synthetic materials such as nylon. One material that is found to be effective is a polyester material, of the type from which the air bag 22 may be manufactured. The sheet material may be flexible or elastic. Regardless of the type of material used to make the air bag guide 32, the use of the air bag guide 32 can be helpful in reducing friction on the air bag 22 as it deploys. Although a polymer such as nylon may be particularly beneficial, even a fleece material will help reduce the friction on the air bag 22. This is because the air bag guide 32 inhibits contact between the deploying air bag 22 and the seat pad 16 and helps to prevent small particles from separating from the seat pad and being introduced into the vehicle compartment.

In at least one embodiment, the inner and outer panels 34, 36 of the air bag guide 32 respectively include rear ends 42, 44 that can be attached suitably to the housing 40 and/or frame 26, and or to each other to effectively associate the air bag guide 32 with the housing 40 of the air bag assembly 20. As best shown in Figure 2, in this illustrated embodiment, the rear ends 42, 44 are attached to each other behind the air bag assembly 20. Alternatively, the inner and outer panels 34 and 36 could be opposite ends of an unitary sheet that wraps around the housing 40, such as is illustratively shown in Figure 8.

In the embodiment illustrated in Figures 5-7, the inner and outer panels 34, 36 of the air bag guide 32 respectively include a plurality of tabs 52, 54 attached to the trim cover 18 adjacent the release seam 28 so that the tabs are adjacent each other and face in the same direction. As will be explained further below, the tabs 52 and 54 in the embodiment illustrated in Figure 8 are adjacent each other and face in opposite directions. The tabs 52, 54 of the inner and outer panels 34, 36 can be attached to the trim cover 18 by any suitable manner. For instance, the tabs 52, 54 can be attached to the trim cover 18 adjacent the tear seam 28 via stitching, ultrasonic welding, adhesive, etc., among other suitable manners. Also, in one embodiment, the trim cover 18 could be secured to the tabs 52, 54 of the air bag guide 32 via in situ molding of a polymeric seat pad 16.

As can be seen in the embodiments illustrated in Figures 5-8, the tabs 52, 54 of the panels 34 and 36 are attached to the trim cover 18 on the same side of the release seam 28. While the embodiment illustrated in Figures 5-8 shows the air bag guide 32 attached to the trim cover 28 on the front trim panel 21 side of the release seam 18, it should be understood that the arrangement could be laterally reversed, i.e., the mirror image, such that the panels 34 and 36 could be attached to the side trim panel 23 of the release seam 28. In at least the embodiment illustrated in Figure 5, the tabs 52 of the inner panel 34 are connected directly to the forward end 60 of the front panel 21 of the trim cover 18 and the tabs 54 of the outer panel 36 are connected directly to the forward end 60 of the front panel 21 adjacent the release seam 28. Thus, all of the tabs 52, 54 of the inner and outer panels 34 and 36 are connected to the trim cover 18 on one (the same) side of the release seam 28. In an alternative embodiment, the tabs 52, 54 can be attached to opposite sides of the release seam, such as show in Figure 4 where tabs 52 are secured to the front trim panel 21 and the tabs 54 are secured to the side trim panel 21. Regardless of whether the tabs 52, 54 are secured to one or both sides of the release seam, as best shown in Figures 6-8, in at least certain embodiments, the tabs 52 are spaced apart with a respective one of tabs 54 being spaced within adjacent tabs 52. Figure 7 shows the embodiment illustrated in Figure 5, where the tabs 52 and 54 face the same direction, i.e., towards the end of the forward end 60 of the front panel 21. Figure 8 shows an alternative embodiment where the tabs 52 and 54 face in opposite directions. In the embodiment shown in Figure 8, one of the panels, such as inner panel 34, faces away from the seam 28 while the other panel, such as outer panel 36, faces the end of the forward end 60 of the front panel 21.

Stitching 7, 9 and 11 can be used to connect the tabs 52 and 54 of the panels 34 and 36 to one or both of the panels 21 and 23, as the case may be, of the trim cover 18. The stitching 7,9, and 11 can be applied in any suitable manner. One suitable manner will be described below where the tabs 52, 54 are secured to one side of the release seam 28, and specifically the front trim panel 21. However, it should be understood that the tabs 52, 54 could be secured to the side trim panel 23 or both trim panels 21 and 23 in the same or similar manner. In one embodiment, stitching 7 is support stitching that is optionally first applied to the front trim panel 21 and the tabs 52 and 54 of the inner and outer air bag guide panels 34 and 36 to secure panels 34 and 36 to the front trim panel 21 of the trim cover 18. This stitching 7 could be a conventional tacking seam, such as by stitching, or an ultrasonic weld. Stitching 9 is then applied to secure the side panel 23 to the front trim panel 21 and the panels 34 and 36. Stitching 11 is then applied, such as in a French seam, to secure the outer, or intermediate, portion 66 of the front trim panel 21 to the forward end 60 of the front trim panel 21 and the panels 34 and 36. Though not shown, an optional French-type seam can be provided on the side trim panel 23.

In at least one embodiment, the air bag guide 32 is effective to prohibit all contact between the deploying air bag 22 and the seat pad 16. This can help to prevent energy loss from the air bag 22 by decreasing friction and protecting the seat pad 16 from damage. This, in turn, can also help to reduce the deployment time for the air bag 22 and/or the amount of inflation fluid required to deploy the air bag.

In at least one embodiment, the inner and outer panels 34 and 36 of the air bag guide 32 form a deployment channel 38 for the air bag 22. As best shown in Figures 2-4, the deployment channel 38 is oriented to facilitate deployment of the air bag 22 through the seam 28 in the trim cover 18. The panels 34 and 36 aid in tearing the release seam 28 by directing the deployment force of the air bag 22 to the release seam 28. In certain embodiments, the trim cover 18 can be made of a material that is more stretchable than the panels 34, 36. Upon deployment of the air bag assembly 20, as shown schematically in Figure 3, the deploying air bag 22 causes relative movement of the flexible inner and outer panels 34 and 36 away from each other which then provide a guiding function of the unfolding air bag 22 as it moves between the panels toward the air bag release seam 28 and eventually tears open the release seam for outward projection of the air bag to provide the occupant protection. Furthermore, as the air bag 22 deploys through the deployment channel 38, the air bag guide 32 acts as a blocking member that forms a barrier on two sides 39, 41 of the air bag 22, thereby inhibiting contact between the air bag 22 and the seat pad 16. Thus, the seat pad 16 is moved away from the air bag 22 as it deploys through the deployment channel 38. As shown in Figures 3-4, the attachment of the tabs 52, 54 to the seam

28 helps to facilitate deployment of the air bag 22 through the seam 28. This is because the deployment channel 38 opens as the air bag 22 is deployed, and this causes the release seam 28 to rupture directing the deploying air bag 22 to exert an outward force on the trim cover 18 at the seam 28; this helps to open the seam 28 to provide an easy exit for the air bag 22. Also attachment of the panels 34, 36 to the release seam 28 helps to ensure that the air bag 22 will deploy in the predetermined desired manner through the seam 28. Because the panels 34, 36 are connected to each other with the same connection or stitching, as the case maybe, as the trim panels 21 and 23 are connected to each other, relatively consistent deployment of air bag in seat assemblies 10 employing the air bag guide 32.

As best shown in Figures 5-8, the seam 28 can be sewn, or otherwise attached, adjacent end portions of the panels 34, 36 of the air bag guide 32 where the end portions of panels 21 and 23 of trim cover 18 are attached to each other via stitching 9 to form the release seam 28 of the trim cover 18. This helps to transfer the force from the air bag guide 32, and facilitates separation of the seam 28.

Referring to Figure 9, one embodiment of an air bag guide 32 is illustrated. In this embodiment, the air bag guide 32 comprises a unitary sheet of material 70, such as flexible material, having a mid point 72 that effectively divides the sheet 70 into inner and outer panels 34 and 36, respectively. Various aspects of the tabs 52 and 54 will be described below with reference to the unitary guide illustrated in Figure 9, however it should be understood that these aspects apply equally to other embodiments of the air bag guide, such as one with separated panels 34 and 36. Moreover, while the air bag guide 32 has been described and illustrated as being a unitary sheet or two separate inner and outer sheets, it should be understood that the air bag guide could comprise a plurality of spaced apart strips, such as 0.5 to 10 cm wide strips, with each end being a tab 52 and 54 and that the various aspects of the tabs described below also apply to this embodiment as well.

Each of the panels 34, 36 have a generally straight edge portion 74 and 76, respectively. The tabs 52 and 54, extend from the generally straight edge portions 74, 76, respectively. The tabs 52 and 54 may have any suitable shape and size. However, in one embodiment, the tabs 52, 54 have a length 1 of 0.5 to 5.0 cm and a height h of 0.5 to 10 cm, and in other embodiments a length 1 of 1.0 to 3.0 cm and a height h of 1.5 to 4 cm. Furthermore, the tabs 52, 54 can have any suitable spacing. However, in at least one embodiment, the tabs 52 and 54 are spaced such that when the inner and outer panels 34, 36 are laid adjacent one another, the tabs 52 and 54 interleave each other and have spaced therebetween, as best shown in Figures 6-8. Spacing d between adjacent tabs 52 and 54 can be any suitable distance, and in at least one embodiment is 0.4 to 20 cm, and in other embodiments 0.5 to 2 cm. While a typical spacing d of 1 to 3 cm is found between adjacent tabs 52 and 54 when the tabs are generally uniformly provided, in some embodiments when it is desired to direct the release seam to open first at a predetermined location or protection area, it is possible for some of the adjacent tabs to have a spacing d of 5 to 15 cm, and in other embodiments of 8 to 12 cm, and in yet other embodiments of 9 to 10 cm.

Furthermore, the tabs 52 and 54 can all be of a unitary size, or tabs 52 and 54 could be of a different size, and tabs 52 could vary in size from other tabs 52 as well as tabs 54 could vary in size from other tabs 54. In at least certain embodiments, the inner panel 34 has 1 to 30 tabs 52 spaced 0.4 to 20 cm apart, having an average height h of 0.5 to 25 cm, and an average length 1 of 0.4 to 25 cm. In yet other embodiments, the inner panel 34 has 15 to 17 tabs 52 spaced 0.5 to 3 cm apart, having an average height h of 0.6 to 3 cm, and an average length 1 of 1.5 to 2.5 cm. In at least certain embodiments, the outer panel 36 has 1 to 30 of tabs 54 spaced 0.4 to 20 cm apart, having an average height h of 0.5 to 25 cm, and an average length 1 of 0.4 to 25 cm. In yet other embodiments, the outer panel 36 has 15 to 17 tabs 54 spaced 0.5 to 3 cm apart, having an average height h of 0.6 to 3 cm, and an average length 1 of 1.5 to 2.5 cm.

In at least one embodiment, the tabs 52 and 54 can be arranged adjacent the release seam 28 to provide for selective opening of the release seam 28 in certain areas prior to the opening of other areas. This could be done by providing a lower concentration of tabs 52 and/or 54 at a particular location along the release seam 28 than at one or more of the other locations. For instance, if it was desired to have the thorax area 33 open before the other area 29, 31 and 35 open, the thorax area 33 would have a lower concentration of tabs 52 and/or 54 than in the other areas. The relatively lower concentration of tabs 52 and/or 54 could be achieved by providing less tabs and/or thinner tabs in this area than in other areas. For instance, the average tab concentration in the thorax area, as an example, could be 10% to 30% tabs over a unit length tabs whereas in the other areas the average tab concentration would be 40% to 80% over the same unit length. For instance, for a unit length of 10 cm, the trim panel 21 would have 1 to 3 cm of tabs 52 and 54 secured thereat, whereas 4 to 8 cm of tabs 52 and 54 would be secured over a 10 cm length of one or more other areas of the trim panel 21. In another embodiment, the average tab concentration a first area predetermined to open first could be 15% to 25% over a unit length while being greater, such as 50% to 70%, over the same unit length in the other areas predetermined to open after the first area opens. In certain embodiments, the concentration of the tabs can be 1.5 to 3 times less in the area of first desired openings than in the other areas.

By providing tabs 52 and 54, in at least certain embodiments, the air bag guide 32 provides a more tailored opening pattern and quicker opening due to less force than has been previously available.

While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED IS: 1. A vehicle seat assembly comprising:

a frame;

a seat pad adjacent the frame;

a trim cover extending over at least a part of the seat pad, the trim cover having a release seam adjacent the seat pad;

an air bag assembly mounted on the frame within the trim cover in a spaced relationship from the release seam, the air bag assembly including an inflator and a folded air bag that is inflatable by the inflator to unfold and project outwardly from the seat through the release seam of the trim cover; and

an air bag guide including an inner panel and an outer panel that are each made of flexible material, the inner and outer panels being associated with the air bag assembly, the air bag guide having a plurality of spaced apart tabs connected to the release seam.

2. The vehicle seat assembly of claim 1, wherein the trim cover comprises a front trim panel and a side trim panel connected to each other to form the release seam, a first plurality of the tabs being connected on the front trim panel and a second plurality of the tabs being connected to the side trim panel.

3. The vehicle seat assembly of claim 2, wherein the tabs of the inner panel are connected to the front trim panel and the tabs of the outer panel are connected to the side trim panel.

4. The vehicle seat assembly of claim 1, wherein the trim cover comprises a front trim panel and a side trim panel connected to each other to form the release seam, the tabs being connected to one of the panels on one side of the release seam.

5. The vehicle seat assembly of claim 4, wherein the tabs of the inner and outer panels are connected to one of the side trim panels or the front trim panel of the trim cover.

6. The vehicle seat assembly of claim 1 , wherein the air bag guide comprises a plurality of panels, each of the plurality of panels having opposed end portions, each of the end portions forming a respective one of the plurality of the spaced apart tabs.

7. The vehicle seat assembly of claim 1 , wherein the tabs are 0.5 to 25 cm in height and the inner and outer panels each have 1 to 30 tabs attached to the trim cover adjacent the release seam.

8. The vehicle seat assembly of claim 1 , wherein the tabs are 0.4 to 25 cm in length, 0.5 to 25 cm in height and 0.4 to 20 cm spaced apart.

9. The vehicle seat assembly of claim 1, wherein the tabs are spaced from each other in a predetermined manner to enable the force of a deploying air bag to be concentrated at a predetermined location of the release seam.

10. The vehicle seat assembly of claim 7, wherein the tabs vary in size to enable the force of a deploying air bag to be concentrated at a predetermined location of the release seam.

11. The vehicle seat assembly of claim 9, wherein the trim cover has a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area, the thorax protection area having a lower tab concentration than the other areas.

12. The vehicle seat assembly of claim 9, wherein the trim cover has a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area, the thorax protection area having an average tab concentration of 10% to 30% over a unit length, and the head, shoulder and thorax protection areas each having an average tab concentration of 40% to 80% over the same unit length.

13. A vehicle seat assembly comprising: a frame;

a seat pad adjacent the frame;

a trim cover extending over the seat pad and including at least a side panel and a front panel cooperating to form a release seam adjacent the seat pad, the trim cover having a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area, the trim cover having an outer surface and an inner surface;

an air bag assembly within the trim cover in a spaced relationship from the release seam, the air bag assembly including an inflator and a folded air bag that is inflatable by the inflator to unfold and project outwardly from the seat through the release seam of the trim cover; and

an air bag guide including an inner panel and an outer panel, the inner and outer panels each having tabs at a forward end, the inner and outer panels having the rear ends connected to each other behind the air bag assembly, and the tabs of the inner and outer panels being connected to the release seam in an alternating manner.

14. The vehicle seat assembly of claim 13, wherein the tabs vary in size to enable the force of a deploying air bag to be concentrated at a predetermined location.

15. The vehicle seat assembly of claim 13 , wherein the trim cover has a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area, wherein one of the protection areas has a lower tab concentration than the other areas.

16. The vehicle seat assembly of claim 13, wherein the air bag guide comprises a unitary one-piece flexible sheet that wraps around the air bag assembly with inner and outer panels being opposite ends of the unitary flexible sheet.

17. A method of making a vehicle seat assembly, said method comprising:

providing a frame;

mounting a seat pad on the frame; disposing a trim cover over the seat pad, the trim cover having a head protection area, a shoulder protection area, a thorax protection area, and a pelvis protection area, the trim cover having a release seam adjacent the seat pad;

providing an air bag assembly adjacent the frame within the trim, the air bag assembly including an air bag that is inflatable to project outwardly from the seat through the release seam of the trim cover; and

providing an air bag guide including a first panel and a second panel of sheet material having forward ends comprising a plurality of tabs, associating the air bag guide with the air bag assembly, and connecting the tabs of the air bag guide to the release seam, the tabs being spaced in such a manner so that, upon deployment of the air bag, one of the protection areas of the release seam will open before the others protection areas.

18. The method of claim 17, wherein the one protection area has a lower tab concentration than the other protection areas.

19. The method of claim 17, wherein the one protection area comprises the thorax protection area.

20. The method of claim 17, wherein the trim cover comprises a front trim panel and a side trim panel connected to each other to form the release seam, the tabs being connected on one side of the release seam to one of the trim panels, the one protection area having a tab concentration of 1.5 to 3 times less than the other areas of protection.