Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-06-25
2004-04-06
Culbreth, Eric (Department: 3616)
Land vehicles
Wheeled
Attachment
Reexamination Certificate
active
06715790
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a side curtain air bag arranged to deploy along the side of a vehicle to protect occupants during a crash involving the vehicle, including a rollover. The side curtain air bag may even wrap around a front-seated occupant, i.e., have a frontal portion designed to deploy between a front-seated occupant and the dashboard.
The present invention also relates to an air bag having a number of interconnected compartments for use in vehicular crashes whereby the air bag deploys before or during the crash to cushion the occupant of the vehicle and prevent injury to the occupant. The invention also relates to a method for making an air bag having interconnected compartments and an occupant protection system including an air bag with interconnected compartments.
The present invention also relates to a vehicular air bag having a low mass and made substantially from thin plastic film which is designed to deploy in a collision involving the vehicle so that if it impacts the occupant of the vehicle wherever he/she is located, it will not cause significant injury to the occupant. In order to make a film air bag of sufficiently low mass so as not to injure the occupant, it has been recognized that the film air bag must contain means to arrest the propagation of a tear so that a small hole or break in the film does not result in a catastrophic failure, i.e., cause the air bag to burst like a balloon or otherwise prevent the air bag from deploying properly. One particular method of arresting the propagation of a tear of this invention is to use a combination of an elastomeric film and reinforcement means which in certain embodiments may be the elastomeric material itself constructed in a variable thickness pattern, i.e., have thinner and thicker sections, or in a manner so that it has strategically placed thicker sections, i.e., relative to remaining portions of the material, in view of stress considerations during deployment.
2. Description of Prior Art
A conventional driver side air bag (also referred to herein as a driver air bag) is made from pieces of either Nylon or polyester fabric that are joined together, e.g., by sewing. The air bag is usually coated on the inside with neoprene or silicone for the purposes of (i) capturing hot particles emitted by the inflator in order to prevent holes from being burned in the fabric, and (ii) sealing the air bag to minimize the leakage of an inflating gas through the fabric. These air bags are conventionally made by first cutting two approximately circular sections of a material having a coating on only one side and which will form a front panel and a back panel, and sewing them together with the coated side facing out. The back panel is provided with a hole for attachment to an inflator. Fabric straps, called tethers, are then sewn to the front panel. Afterwards, the air bag is turned inside out by pulling the fabric assembly through the inflator attachment hole placing the coated side on the inside. Assembly is completed by sewing the tethers to the back panel adjacent the inflator attachment hole.
If a conventional driver air bag is inflated without the use of tethers, the air bag will usually take an approximately spherical shape. Such an inflated air bag would protrude significantly into the passenger compartment from the steering wheel and, in most cases, impact and injure the driver. To prevent this possible injury, the tethers are attached to the front and rear panels of the air bag to restrict the displacement of the front panel relative to the back panel. The result of the addition of such tethers is an air bag that has the shape of a flat ellipsoid with a ratio of the thickness of the air bag to its diameter of approximately 0.6. In the conventional air bag, the tethers are needed since the threads that make up the air bag fabric are capable of moving slightly relative to each other. The air bag is elastic for stresses that are not aligned with the warp or woof of the fabric. As a result, the fabric would distort to form an approximate sphere in the absence of such tethers.
Moreover, the above-mentioned method of manufacturing an air bag involves a great deal of sewing and thus is highly labor intensive and, as a result, a large percentage of all driver air bags are presently manufactured in low labor cost countries such as Mexico.
Many people are now being injured and some killed by interaction with the deploying air bag (See, e.g., “Warning: Too Much Safety May Be Hazardous”, New York Times, Sunday, Dec. 10, 1995, Section F, Page 8). One of the key advantages of the film air bag described in the current assignee's above-referenced patents and patent applications is that, because of its much lower mass than conventional Nylon or polyester fabric air bags, the injury caused by this interaction with the deploying air bag is substantially reduced. In accordance with the teachings of those patents and patent applications mentioned above, the driver air bag system can be designed to permit significant interaction with the driver. In other words, the film air bag can be safely designed to intrude substantially further into the passenger compartment without fear of injuring the driver. Nevertheless, in some cases, as described in U.S. Pat. No. 5,653,464, it may be desirable to combine the properties of a film air bag, which automatically attains the conventional driver air bag shape, with a fabric air bag. In such cases, interaction with the driver needs to be minimized.
Air bag systems today are designed so that ideally the air bag is fully inflated before the occupant moves into the space that is occupied by the air bag. However, most occupants are not positioned at the ideal location assumed by the air bag system designer, and also may not have the dimensions, e.g., size and weight, in the range considered for optimum air bag deployment by the air bag system designer. Many occupants sit very close to the air bags, or at least closer than expected by the air bag system designer, and as mentioned above, are injured by the air bag deployment. On the other hand, others sit far from the air bag, or at least farther away from the air bag than expected, and therefore must travel some distance, achieving a significant relative velocity, before receiving the benefit of the air bag. See for example “How People Sit in Cars: Implications For Driver and Passenger Safety in Frontal Collisions—The Case for Smart Restraints.”, Cullen, E., et al 40
th
Annual Proceedings, Association For the Advancement of Automotive Medicine, pp. 77-91.
With conventionally mounted air bags such as those mounted in the steering wheel or instrument panel, severe out-of-position occupant situations, where the occupant is resting against the air bag when deployment begins, can probably only be handled using an occupant position sensor, such as disclosed in the current assignee's U.S. Pat. No. 5,653,462 (corresponding to published WO 94/22693), which is incorporated herein by reference, which prevents an air bag from deploying if an occupant is more likely to be seriously injured by the air bag deployment than from the accident itself. In many less severe accidents, the occupant will still interact with the deploying air bag and sustain injuries ranging from the mild to the severe. In addition, as mentioned above, some occupants sit very far from the steering wheel or instrument panel and, with conventional air bags, a significant distance remains between the occupant and the inflated air bag. Such occupants can attain a significant kinetic energy relative to the air bag before impacting it, which must be absorbed by the air bag. This effect serves to both increase the design strength requirements of the air bag and increase the injury induced in the occupant by the air bag. For these reasons, it would be desirable to have an air bag system that adjusts to the location of the occupant and which is designed so that the impact of the air bag causes little or no injury to the occupant.
It
Automotive Technologies International Inc.
Culbreth Eric
Fleming Faye M.
Roffe Brian
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