Front pillar trim panel with tether

[0001] The present invention relates to a vehicular interior trim panel, for example, a front A-pillar trim panel used to cover a side curtain airbag having a tether to prevent complete detachment of the trim panel into the passenger compartment.

[0002] Inflatable restraint devices, commonly called airbags, are standard equipment on most new vehicles. As consumer's concerns for safety have increased, additional airbags have been employed in different areas of the vehicle other than in the steering wheel and the passenger side of the instrument panel. Side curtain airbags have grown in popularity due to the lack of a crush zone and energy dissipation capacity in the sides of vehicles. Side curtain airbags have been employed or stored in areas of the roof rails and headliners or in the side doors. These airbag devices are typically concealed from occupant view by interior trim panels.

[0003] Interior trim panels concealing the air bag devices are a challenge for designers and engineers due to the competing interests of permitting the airbags to be easily deployed in the desired areas while maintaining aesthetic appeal of the vehicle passenger compartment. The trim panels must also be capable of enduring the explosive forces of air bag devices without being dislodged from the vehicular structure that they are attached to and potentially entering the passenger compartment. These challenges are accentuated in the front A-pillar area of vehicles due to the limited space and position proximate to the driver and front passenger.

[0004] Known trim panel and instrument panel designs for concealing air bag devices have included rupturable covers, for example, in steering wheel and passenger side frontal airbags deployable from the instrument panel as well as other interior trim panels. These devices have included so-called tethers or other devices which attempt to prevent the trim panel, or portions thereof, from detaching from their attachment points to the vehicle or a portion of the trim panel from breaking off and detaching under the explosive forces imparted by the airbag.

[0005] The known devices suffer from several disadvantages including the tethers being applied to the outer surface of the trim panel, i.e. the side toward the interior of the passenger compartment visible by the occupants, and use of separate straps providing a second or auxiliary attachment of the trim panel to the vehicle through use of mechanical fasteners. Tethers attached to the outer surface of the trim panel create difficulties in applying an exterior coating or covering over the trim panel to make it more aesthetically appealing and use of additional mechanical fasteners adds costs and additional assembly time in the manufacture of the vehicle.

[0006] It would be desirable to provide an interior trim panel with a tether to prevent detachment of a portion of the trim panel and potential entry into the passenger compartment that is easily integrated into the manufacturing process of the trim panel and does not interfere with the aesthetics of the panel or require secondary attachment of the tether to the vehicular structure. It is further desirable to have an interior trim panel with these advantages that is useable in the front A-pillar region of the passenger compartment for use with side curtain airbags that deploy from the side roof rail region by the driver and passenger side windows adjacent the windshield.

[0007] In one embodiment of the invention, a trim panel is attached in selected areas to the body structure of the vehicle. The trim panel includes an integral first portion and a second portion that include an outside surface toward the passenger compartment and an inside surface toward the body structure not visible by the occupants. The first and second panel portions are joined in a frangible area creating a notch or hinge on the inside surface of the trim panel out of view of the occupants. This notch or hinge area permits the second portion to rotate away from the airbag on expansion of the airbag to provide a passageway for the airbag to expand out from behind the trim panel toward its desired location.

[0008] The trim panel includes a tether for attachment to the first and second portions of the trim panel. In one embodiment, the tether is integrally molded into the trim panel during the manufacture of the trim panel so as to not affect the aesthetic appearance of the trim panel to the occupants. In one embodiment, the tether is positioned toward the middle of the panel away from both the outer surface and the inner surface of the trim panel.

[0009] In another embodiment, the tether is integrally molded into the trim panel as described above, but is substantially located at the inner surface of the trim panel adjacent the vehicle structure the trim panel is attached to.

[0010] In another embodiment, the tether is not integrally molded into the trim panel material, but securely attached to the inner surfaces of the trim panel portions through conventional processes.

[0011] Regardless of the method of attachment of the tether to the trim panel, either integrally molded or conventionally attached, the tether interconnects the first portion and the second portion across the frangible portion of the trim panel. The connection of the first and second portions by the tether, or tethers, prevents the second portion from being completely detached from the first portion in the event the second portion fractures or breaks away from the first portion.

[0012] Other applications of the present invention will become apparent to those skilled in the field when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.

[0024] Referring to FIGS. 1-10, several embodiments of a trim panel having a tether are illustrated for use as a vehicular interior trim panel in the front A-pillar region of the passenger compartment used to cover a side curtain airbag. Referring to FIGS. 1 and 2, an interior trim panel with tether 10 is illustrated. Trim panel 10 is positioned, for example, in the front A-pillar portion 14 of the vehicle passenger compartment and covers a side curtain air bag 12 mounted in the roof rail and A-pillar regions behind the trim panel 10. In this position, the trim panel 10 is positioned adjacent the instrument panel 16, windshield 18 and driver side door (not shown).

[0025] Trim panel 10 includes a forward portion 20 (toward the front of the vehicle), a rearward portion 22 (toward the rear of the vehicle), an upper portion 24 (toward the headliner and roof of the vehicle) and a lower portion 26 (toward the instrument panel 16). Trim panel 10 further includes an outer surface 28 (toward the interior of the passenger compartment generally visible by the occupants) and an inner surface 30 (toward the exterior of the vehicle generally not visible by the occupants in normal conditions). The inner surface 30 is adjacent the A-pillar vehicle body structure 15, typically welded sheet metal, positioned behind the trim panel as best seen in FIGS. 5, 7 and 9. Inner surface 30 and A-pillar structure 15 define a chamber 36 sufficient to house or store airbag 12.

[0026] Trim panel 10 may be made from polypropylene, polyethylene or other polymers or elastomers, or combinations thereof, known by those skilled in the art. Trim panel 10 may be manufactured by injection molding or other molding processes known by those skilled in the art. It is contemplated that trim panel 10 may be useful in other trim panel applications other than in the front A-pillar regions as illustrated and described and can take other forms without deviating from the invention.

[0027] The trim panel 10 outer surface 28 and inner surface 30 define a general first thickness 32 between the outer surface 28 and the inner surface 30 as best seen in FIG. 6. It is understood that due to the nature of the trim panel part and manufacturing processes used, this general first thickness may vary slightly in different areas of the trim panel 10.

[0028] Referring to FIGS. 3, 4 and 5, trim panel 10 includes an integral first panel or first portion 42 and a second panel or second portion 44. First portion 42 is integrally joined to second panel 44 along a frangible portion or area 40 which forms an elongate and natural hinge 50 as best seen in FIGS 3, 4 and 6. In a preferred embodiment, frangible portion 40 is, for example, created by a notch or hinge 50. As best seen in FIGS. 6 and 10, frangible portion 40 generally has a second thickness 34 less than the immediately surrounding first thickness 32 as best seen in FIG. 6. In one embodiment, the hinge 50 is positioned on the inner surface 30 of trim panel 10 so as not be visible by the vehicle occupants, In one embodiment, hinge 50 is positioned along substantially the entire length of trim panel 10 between the upper 24 and lower 26 regions as vest seen in FIGS. 1, 3 and 4. Frangible portion 40 is positioned on the inner surface 30 creating hinge 50 along the outer surface 28 along an equal length of trim panel 10. It is understood that the location and orientation of frangible portion 40 and hinge 50 may vary depending on the application of trim panel 10 and the type, position and intended expansion of side curtain airbag 12. It is further understood that hinge 50 may be formed by structural configurations other than a localized reduction of thickness in the form of a notch, for example, structural configurations that would concentrate the stresses in the desired area to produce a hinge effect know by those skilled in the art.

[0029] In one embodiment, trim panel 10 is attached to the front vehicle A-pillar structure 15 through the first portion 42 by fasteners 38 generally shown in FIGS. 1, 5, 7 and 9. The fasteners are typically polymer clips but may be other types of fasteners known by those skilled in the art.

[0030] Referring to FIGS. 1 and 5-10, Trim panel 10 further includes a tether 60. In one embodiment, tether 60 is integrally molded into trim panel 10 and is positioned in the first thickness 32 at a desired location depending on various factors including the trim panel 10 material used, the first 32 and second 34 thicknesses, the geometry of trim panel 10, the tether 60 material, the type and deployment of the airbag 12 and other factors known by those skilled in the art. In a preferred embodiment for trim panels to be manufactured, the tether 60 is integrally molded into and positioned between the outer surface 28 and the inner surface 30 as best seen in FIGS. 5-7. In this embodiment, tether 60 is positioned approximately in the middle of the first thickness 32 adjacent to and spanning across the frangible portion 40 as best seen in FIG. 6. In this embodiment, tether 60 extends substantially the entire length of trim panel 10 along frangible portion 40 as generally shown in FIG. 1. It is understood that tether 60 may cover a greater or lesser area than the entire length of trim panel 20 or the illustrated width across trim panel 10 as generally shown in FIG. 1. It is further understood that tether 60 may be one continuous piece or several separate pieces. It is understood that tether 60 will at least interconnect or cover a part of the first portion 42 and second portion 44 to prevent complete detachment of second portion 44 from first portion 42 as described more fully below.

[0031] As best seen in FIG. 8, tether 60 is preferably made from a sheet of flexible fabric material having a selected surface area 64. The selected surface area and size of tether 60 is sufficient to cover or span at least a portion of frangible portion 40. In this embodiment, tether 60 is preferably made from a woven, fibrous material 62 such as nylon. The tether 60 material has the capability to be incorporated into the typical molding process or attachment to trim panel 10 as described later. The tether 60 material must be relatively flexible and capable of withstanding the forces exerted by the expansion of airbag 12 without substantial fracture or tearing. It is understood that other materials, of different properties, sizes and orientations may be used having these general characteristics known by those skilled in the art without deviating from the invention.

[0032] In another embodiment, not shown, tether 60 is integrally molded into trim panel 10 as generally described above. In this embodiment, tether 60 is positioned toward and is substantially in contact with the inner surface 30.

[0033] Referring to FIGS. 1, 9 and 10, another embodiment of trim panel 10 is illustrated. In this embodiment, tether 60 is not integrally molded into first thickness 32, but is attached to the inner surface 30 spanning at least a part of the frangible portion 40 as best seen in FIG. 10. In this embodiment, tether 60 may similarly extend along substantially the entire length of trim panel 10 as generally shown in FIG. 1 and previously described. Tether 60 may be attached to inner surface 30 through adhesive, ultrasonic bonding, staking and other attachment methods known by those skilled in the art.

[0034] Referring to FIG. 2, in operation, trim panel 10 normally covers or conceals the vehicular front A-pillar 14 body structure 15 and the side curtain airbag 12 while providing an aesthetically pleasing appearance for the occupants. In the preferred embodiment, the airbag 12, frangible portion 40, hinge 50, and tether 60 are not visually perceptible from the outer surface by the occupants.

[0035] On ignition of the airbag safety device system, the airbag begins to rapidly expand. In the side curtain airbag 12 of the preferred embodiment, airbag 12 expands in a generally downward direction with significant force. As best seen if FIGS. 3, 4 and 7, on contact of airbag 12 with the lower portion of trim panel 10 inner surface 30, the second portion 44 is pushed in a downward or downward and rearward direction. Stress on the trim panel 10 is concentrated at the frangible portion 40. As best seen in FIGS. 3, 4 and 7, second portion 44 is forced to rotate with respect to first portion 42 about hinge 50 in a direction away from airbag 12 along the length of trim panel 10. The permitted and controlled rotation of second portion 44 allows a passageway for airbag 12 to expand to the desired position. The permitted and controlled rotation of second portion 44 further permits first portion 42 to remain securely attached to the A-pillar body structure 15 through fasteners 38.

[0036] On rotation of second portion 44 as described, tether 60 flexes or bends along hinge 50 as second portion 44 rotates away from airbag 12. As best seen in FIG. 7, in the event that there is a fracture of trim panel 10 along frangible portion 40, or in any area covered by tether 60, tether 60 remains attached to the first portion 42 and the second portion 44 thereby preventing the second portion 44 from complete detachment from first portion 42 and the possibility of entering the passenger compartment.

[0037] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.