Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-06-11
2001-07-17
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S728100, C280S732000
Reexamination Certificate
active
06260875
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to an air bag door that is integrally formed with a vehicle trim panel, and, more particularly, to such an air bag door configured to break and/or tear open in a predictable way and a method for making such a door.
INVENTION BACKGROUND
It is desirable for inflatable restraint systems having intergrally formed air bag doors to include some means of insuring that the air bag doors break and/or tear open in a generally predictable way. This is true for driver-side inflatable restraint systems (DSIRs), passenger-side inflatable restraint systems (PSIRs) and inflatable restraint systems in vehicle door panels, quarter panels; other sidewall structures, seats, headliners, pillars, etc. The air bag doors in such systems open to provide a path for an air bag to deploy through. It is also desirable for such systems to include means for insuring that portions of the door do not separate from the system when an air bag deploys and forces the door open.
To develop tearing and/or breaking, air bag doors that are integrally formed with automotive trim or instrument panels will sometimes include regions of weakened materials, reduced thickness or scoring, all of which are commonly referred to as “tear seams.” Tear seams are weak areas designed to tear and/or break when an air bag inflates and forces the door to open. Some of these systems also employ tethers and/or hinges that retain the air bag door to the instrument or trim panel after the door has torn and/or broken open. For example, U.S. Pat. No. 5,569,959, issued to Cooper et al., discloses an inflatable restraint assembly comprising an air bag door retainer portion integrally formed in an automotive instrument panel retainer and defined by a door seam. A tear guide is included in a skin cover disposed over a foam layer that extends across the door opening. A metal hinge panel is embedded within the instrument panel retainer and spans a portion of the door seam. Cooper et al. also disclose a method for making such an inflatable restraint assembly. The method includes pre-molding the hinge panel into the hard instrument panel retainer portion such that the hinge panel spans the door seam.
With many current systems, the tear seams and/or hinges are formed in a hard instrument panel retainer portion. They may be created during molding or can be done by a secondary operation such as cutting, grinding or laser scoring performed after a manufacturing step of integrally molding the instrument panel and door. Current systems also include tear seams formed in back surfaces opposite the outer class-A surfaces of integral instrument panel/air bag door structures to improve the aesthetic appearance of the instrument panel by concealing the presence of the door.
To date, most tear seams formed in hard instrument panel retainers during molding are created via a reduced thickness of material. However, this method has proven unreliable where the structure of one side of the tear seam is limited to the nominal thickness of the panel. In such an instance the tearing action tends to leave the path of the intended seam which is unacceptable. Consequently, secondary operations are often used to increase the repeatability and robustness of the tear seam which has the negative impact of cutting cost.
At least one automotive instrument panel, as shown and described in U.S. Pat. No. 5,162,092, issued to Klobucar et al., discloses an instrument panel having a gas channel and a method for forming the channel in the panel. The gas channel is a tubular structure integrally formed in the panel by injecting gas into molten panel material in a mold. The gas channel in the Klobucar et al. instrument panel adds structural rigidity. However, Klobucar et al. does not disclose an air bag door or any other supplemental inflatable restraint component.
What is needed is a supplemental inflatable restraint system that includes an integrally formed air bag door having retaining structure that retains the door during air bag deployment and that can be formed with the air bag door instead of requiring a secondary operation. What is also needed is such a system that includes tear-guiding structure that guides tearing during air bag deployment and that can be formed with the air bag door instead of requiring a secondary operation.
INVENTORY SUMMARY
According to the present invention an inflatable restraint assembly is provided for passengers in automotive vehicles that includes a hinge comprising a first material and a second material embedded at least partially within the first material and spanning a door seam. The assembly also includes an air bag door integrally formed in an automotive instrument panel comprising the first material. The integral air bag door is defined at least in part by a tear guide when the door is in a closed position. The air bag door is movable from the closed position to provide a path for an air bag to deploy through and is movable out of the closed position by at least partially separating from the instrument panel along a door seam at least partially defined by the tear guide. A retaining structure is configured to preclude at least a portion of the air bag door from departing the immediate vicinity of the instrument panel during air bag deployment.
According to another aspect of the invention the hinge is configured to be at least substantially invisible as viewed from the outer class-A surface of the instrument panel. This improves the aesthetic appearance of the class-A surface and discourages tampering.
According to another aspect of the invention the hinge includes a first end embedded in a portion of the first material that forms the door and a second end embedded in a portion of the first material that forms the instrument panel. A mid portion of the hinge is disposed between the first and second ends and has an outer surface covered with a portion of the first material that forms the outer class-A surface of the door and instrument panel. The mid portion also has an exposed inner surface disposed opposite the outer surface that is not covered with the first material.
According to another aspect of the invention the second material includes any one or more materials from a group of materials including thermoplastic rubber, glass matte, fabric and metal
According to another aspect of the invention a skin layer is supported on the trim panel and a foam layer may be disposed between the trim panel and the skin layer.
According to another aspect of the invention, the trim panel includes a second generally tubular channel disposed generally parallel to the first tubular channel and along a side of the hinge opposite the first tubular channel.
According to another aspect of the invention the tear guide comprises a region of reduced strength that guides tearing during air bag deployment. A first generally tubular channel is disposed along the tear guide to create a substantial strength differential with the door seam. This helps to insure that tearing and breakage is confined to the tear seam.
According to another aspect of the invention the first tubular channel includes an elongated arcuate outer wall. The arcuate outer wall includes no sharp edges.
According to another aspect of the invention the tear guide comprises a region of reduced thickness. Reducing thickness allows strength to be reduced without incorporating a second, weaker material.
According to another aspect of the invention the first tubular channel is disposed opposite an outer class-A surface of the air bag door and instrument panel. Again, this helps preserve the aesthetic appearance of the outer class-A surface of the air bag door and instrument panel
According to another aspect of the invention a second generally tubular is disposed adjacent and parallel to the first tubular channel, the tear guide being disposed between the first and second tubular channels.
According to another aspect of the invention the tear guide is defined by an elongated gap disposed between the first and second tubular channels. In other words, the gap it
Daniels Vernon A.
Kennedy John J.
Morren Nelson J.
Stawicki Edwin V.
Culbreth Eric
Reising Ethington Barnes Kisselle Learman & McCulloch PC
Textron Automotive Company
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