AIR BAG CONSTRUCTION

Abstract: A temper-resistant cover (12) for an airbag (16) includes one or more regions (8) in a surface of the tamper-resistant cover that is/are less tear-resistant than the material which is used throughout the remaining portions of the cover. This tearable portion (8) or portions readily rips upon deployment of the airbag when pressurized gas rapidly fills the underlying airbag thereby allowing rapid deployment of the airbag as desired. Selective locations for the tearable region or regions on the cover desirably may be used to assist in altering the way in which the airbag deploys during a crash or other impact. The tearable regions on the bag cover may be formed by providing mechanical wear to the desired region on the cover. Alternatively, the tearable region or regions may be formed by creating an ultra-sonic tear seam or through the use of a tear tab (33) or tear strip (25) into the cover.

Description: TITLE OF THE INVENTION AIR BAG CONSTRUCTION BACKGROUND OF THE INVENTION Field Of The Invention The present invention is generally directed to the field of automatic airbag deployment systems. More specifically, the present invention is directed to an airbag housing having a cover which tears open when the airbag fills with pressurized gas during deployment. Description of the Related Art Airbag deployment systems are generally known in the field and have been widely used in the automobile industry. The majority of these deployment mechanisms employ a cover which separates from a top of a housing that encloses an airbag prior to deployment. More recently, airbags have been suggested for use in aircraft where they will be deployed directly from seatbelts in front of passengers. Currently, there is no existing cover that is both aesthetically pleasing and tamper- resistant but yet will not interfere with the deployment of the airbag for air bags that are deployed from a seat belt location. The cover must deploy with minimum resistance and must not cause injury to an occupant during deployment of the airbag. The cover must also not shread the fabric of the airbag during deployment while also being tamper resistant yet aesthetically pleasing. Accordingly, there remains a need in the art for a cover which can be used as an enclosure for an airbag mounted on a seat belt which satisfies each of the requirements set forth above. The inventors of the present application have discovered an air bag cover for an air bag located on a seat belt that satisfies each of these requirements. It will be apparent to thos.e^skilled in the art that the devices described herein satisfy each of these requirements in light. o ' f the following Summ.ary and Detailed Description of the presently preferred embodiments. SUMMARY OF THE INVENTION In accordance with the present invention, an airbag that is preferably deployed over and or around a top surface of a seatbelt has a tamper-resistant cover. The tamper-resistant cover includes one or more regions in a surface of the tamper-resistant cover that is less tear- resistant than the material which is used throughout the remaining portions of the cover. This tearable portion or portions readily rips upon deployment of the airbag when pressurized gas rapidly fills the underlying airbag thereby allowing rapid deployment of the airbag as desired. The remaining portions of the cover material do not tear as readily as the tearable regions. Alternatively, a connection between two flap members may form the weakened portion of the cover to allow deployment of an airbag from beneath the cover. Advantageously, the cover does not interfere with the deployment of the airbag and also provides a tamper-resistant aesthetically pleasing cover. A further feature and advantage of the tamper-resistant cover of the present invention is that the selective location of the weakened region or regions on the cover desirably may be used to assist in altering the way in which the airbag deploys during a crash or other impact. For example, a tearable portion of the cover may be centrally located on a top surface of the tamper-resistant cover. When tearable portion is located in the central region of the top surface, with out any other such tearable regions on the cover, the bag will initially expand and deploy through the central region of the cover. Alternatively, if a pair of tearable regions are centrally located on two separate sides of the top of the belt, the airbag deployment will occur intially through these two regions .and then expand out therefrom until the cover is opened substantially along its entire length. This feature of the present invention may be used to control deployment of the bag in a predetermined sequence. This may be important if it is desirable to control the application of pressure from the bag on the occupant or internal surfaces of the passenger compartment. Specifically, this feature may be used to control movement of an occupant's body or prevent contact between certain surfaces within the passenger compartment and the passenger. For example, for a passenger located adjacent the right side wall of an airplane, it may be desirable to have the airbag deploy such that the right side of the bag deploys initially and the remaining bag expands out from the expanded right side in order to cushion the passsenger from impact with the side wall. In order to achieve this affect, the bag cover has a tearable portion located on the right side. It will be apparent to those skilled in the art that the weakened region may be placed in a wide variety of locations depending upon the desired effect. The tearable regions on the bag cover may be formed in a variety of different ways. All that is necessary is that the tearable region provide less resistance to tearing than the remaining portions of the cover assembly. For example, the tearable regions may be formed by providing mechanical wear to the desired region on the cover. Alternatively, the tearable region or regions may be formed by creating an ultra-sonic tear seam or through the use of a tear tab or tear strip formed into the cover. It is preferred that the tearable region be formed of an ultra-sonic tear seam formed in a cover comprised of a polymer material. This is preferred because the material will not shread the bag fabric during deployment and will not significantly limit deployment of the bag or cause injury to the occupant. Furthermore, the selection of this material provides a tamper-resistant cover that is also aesthetically pleasing. In a further alternate embodiment, when cover flaps are joined over the top of an airbag and belt structure, the flaps may be joined together with ultrasonic welding or mechanical stitching of tearable elements that either break apart or detach from the flap cover material. The detachment or separation of these elements provides for rapid deployment of an air bag. In one preferred embodiment, T-shaped elements are sewn or welded across a seam between two cover flaps. These T-shaped structures break apart during deployment and allow the flap members to separate. The use of T-shaped connection elements is exemplary only and other connection elements may be used as well. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a first preferred embodiment of the present invention; Figure 2 illustrates a side view of the embodiment of the present invention set forth in Figure 1 ; Figure 3 illustrates a further embodiment of the present invention wherein two sides of a cover are secured to a restraining belt; Figure 4 illustrates a further alternate embodiment of the present invention wherein a unitary member surrounds an airbag and seatbelt assembly; Figure 5 illustrates a side view of the airbag cover illustrated in Figure 4.; Figure 6 illustrates a tear seam in accordance with the present invention; Figure 7 illustrates connection elements for connecting separate cover flap members. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exemplary airbag cover of the present invention is shown generally in Figure 1 at 10. As shown in Figure 1 , an outer airbag cover 12 encloses both a belt type restraining device 14 as well as a folded airbag 16 prior to deployment of the airbag. Preferably, the outer perimeter of the airbag cover is stitched down to the belt restraining device 14. Alternatively, the cover may completely surround the restraining belt and bag assembly. As shown in Figure 1, the cover 12 includes a preferably located central portion 18 where the strength of the material for the outer cover bag has been reduced through, for example, ultrasonic stitching or through chemical treatment, mechanical wear or laser treatment. This weakened portion or region may alternatively be comprised of a connection between separate portions of the cover material that is not as strong as the connection between other portions of the cover material. Advantageously, the weakened portion of the airbag cover provides for the rapid deployment of the airbag through the cover. The selective placement of the weakened portion may also be used in controlling the selective deployment of the airbag. Figure 2 is a side view illustration of the airbag cover mechanism of the present invention. As shown in Figure 2, in this embodiment, the cover 12 completely surrounds the seatbelt 14 as well as an internally located folded airbag 16. The weakened portion or region of the airbag cover having decreased strength 18 is located on the top surface preferably in the center. As noted, the actual location of the cover region 18 having decreased strength may be selected in order to alter initial bag deployment. For example, it is preferred that this region be centrally located to allow for more uniform deployment of the bag in front of a passenger. However, other selections for the location of the cover region having decreased strength may be used as well. As noted above, the fabric cover may be sewn to the restraining belt or the cover member may surround both the airbag 16 and the restraining belt 14. A single piece of cover material may be sewn directly to the restraining belt 14 where mechanical wear or etching or some other technique for decreasing the strength of the airbag cover has been employed for weakening a selected area. Figure 3 illustrates a further alternate embodiment of the invention where the cover material 12 is attached to the underside portions of the belt restraining device 14. The weak portion 18 of the airbag cover 12 is also preferably centrally located in this embodiment. The airbag material may be comprised of a polymer material whose weakened portion 18 has been formed by mechanical wear, laser treatment, chemical etching or ultrasonic stitching. The weakened area 18 will tear first and the bag will deploy and expand initially outward from the weakened region 18. In the embodiment illustrated in Figure 4, the cover 12 is a unitary member which slides over the bag/belt assembly. The ends of this cover material 12 may be stitched to the safety belt 14 in order to limit access to the airbag material thereby making the unit tamper resistant. The weakened portion 18 of this embodiment may also be formed as noted above. It is preferred that this unitary member be formed as a plastic extrusion made from a polymer material. In a further preferred embodiment, the weakened area may be comprised of an integrally molded tear seam wherein a portion of the polymer cover material is less thick than other regions of the cover thereby providing a weakened area that tears initially during deployment of an airbag. Figure 5 is a side view that illustrates this embodiment of the airbag cover 12, wherein the cover has a preferably internally located region 23 that is thinner than the remain portions of the cover 12. Figure 6 illustrates a further alternate embodiment of the present invention which is comprised of a tear seam that may be attached between two portions of the cover material to provide ready separation of the cover regions. In this embodiment, the tear seam 25 is preferably comprised of a polymer material having a preferably located central portion 27 that is thinner th.an the remaining regions. The sides of the tear strip 26, 28 may be secured to cover material via any conventional manner such as, for example, via mechanical stitching, or ultrasonic welding and the like. The tear strip allows two airbag cover portions to readily separate during deployment of the airbag. Figure 7 illustrates yet another alternate embodiment of the present invention wherein T-shaped connection elements 33 are secured between two flaps 36, 38 of cover material. Desirably the T-shaped connection elements 33 have a central portion 40 that is physically smaller than the remaining regions in order to provide a weakened region that will break during deployment of an airbag. The T-shaped members 33 are attached to the adjacent flap members 36, 38 of the cover material via either mechanical stitching or ultrasonic welding or the like. The T-shaped members 33 are preferably secured beneath the top surface of the overlapping flaps, however, those skilled in the art will recognize that they may be formed on the top surface as well. During deployment, as the pressure beneath the flaps 36, 38 increases, the connection elements 33 begin to break and the airbag expands out from the cover, The present invention has been described with respect to the exemplary embodiments and is subject to many variations and modifications that nevertheless fall within the spirit and scope of the appended claims.

Claims: We claim: 1. An airbag cover comprising: at least one sheet of cover material formed over an airbag; and said sheet of cover material having at least one region having a strength that is reduced relative to remaining regions of the cover material. 2. The airbag cover of claim 1 , wherein the region having a strength that is reduced, is formed by laser energy. 3. The airbag cover of claim 1, wherein the region having a strength that is reduced, is formed by mechanical wear. 4. The airbag cover of claim 1, wherein the region having a strength that is reduced, is formed by chemical etching. 5. The airbag cover of claim 1 , wherein the cover is comprised of a unitary member and the region having a strength that is reduced, has a thickness that is lower than a thickness of remaining regions of the cover material. 6. The airbag cover of claim 5, wherein the cover is attached at first and second ends to a restraining belt located within the cover. 7. An airbag cover comprising: first and second portions of cover material, at least one of said first and second portions of cover material located over an airbag; a connection between the first and second portions of cover material, said connection having a strength that is less than a strength of the cover material. 8. The airbag cover of claim 7, wherein the connection is comprised of at least one connection element that is connected to both the first and second portions of cover material. 9. The airbag cover of claim 7, wherein the connection is comprised of a plurality of connection elements that are connected to both the first and second portions of cover material. 10. The airbag cover of claim 9, wherein the connection elements are comprised of T-shaped members. 11. The airbag cover of claim 8, wherein the connection element is comprised of a tear seam formed in a polymer strip and the tear seam has a thickness that is less than remaining portions of the polymer strip.

Inventors: ADKISSON RICK A
Applicants: AM SAFE INC, AM-SAFE INCORPORATED
Application year: 2001
Main classification: B60R21
IPC codes: B60R21