Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-03-27
2001-06-26
Rice, Kenneth R. (Department: 2167)
Land vehicles
Wheeled
Attachment
C280S743200, C280S729000
Reexamination Certificate
active
06250668
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an airbag having a number of interconnected compartments for use in vehicular crashes whereby the airbag 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 airbag having interconnected compartments and an occupant protection system including an airbag with interconnected compartments.
The present invention also relates to a vehicular airbag 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 airbag of sufficiently low mass so as not to injure the occupant, it has been recognized that the film airbag 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 airbag to burst like a balloon or otherwise prevent the airbag 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 airbag (also referred to herein as a driver airbag) is made from pieces of either Nylon or polyester fabric that are joined together, e.g., by sewing. The airbag 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 airbag to minimize the leakage of an inflating gas through the fabric. These airbags 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 airbag 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 airbag is inflated without the use of tethers, the airbag will usually take an approximately spherical shape. Such an inflated airbag 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 airbag to restrict the displacement of the front panel relative to the back panel. The result of the addition of such tethers is an airbag that has the shape of a flat ellipsoid with a ratio of the thickness of the airbag to its diameter of approximately 0.6. In the conventional airbag, the tethers are needed since the threads that make up the airbag fabric are capable of moving slightly relative to each other. The airbag 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 airbag involves a great deal of sewing and thus is highly labor intensive and, as a result, a large percentage of all driver airbags 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 airbag (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 airbag 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 airbags, the injury caused by this interaction with the deploying airbag is substantially reduced. In accordance with the teachings of those patents and patent applications mentioned above, the driver airbag system can be designed to permit significant interaction with the driver. In other words, the film airbag can be safely designed to intrude substantially further into the passenger compartment without fear of injuring the driver. Nevertheless, in some cases, as disclosed in U.S. Pat. No. 5,653,464, it may be desirable to combine the properties of a film airbag, which automatically attains the conventional driver airbag shape, with a fabric airbag. In such cases, interaction with the driver needs to be minimized.
Airbag systems today are designed so that ideally the airbag is fully inflated before the occupant moves into the space that is occupied by the airbag. However, most occupants are not positioned at the ideal location assumed by the airbag system designer, and also may not have the dimensions, e.g., size and weight, in the range considered for optimum airbag deployment by the airbag system designer. Many occupants sit very close to the airbags, or at least closer than expected by the airbag system designer, and as mentioned above, are injured by the airbag deployment. On the other hand, others sit far from the airbag, or at least farther away from the airbag than expected, and therefore must travel some distance, achieving a significant relative velocity, before receiving the benefit of the airbag. 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 airbags such as those mounted in the steering wheel or instrument panel, severe out-of-position occupant situations, where the occupant is resting against the airbag 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 airbag from deploying if an occupant is more likely to be seriously injured by the airbag deployment than from the accident itself. In many less severe accidents, the occupant will still interact with the deploying airbag 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 airbags, a significant distance remains between the occupant and the inflated airbag. Such occupants can attain a significant kinetic energy relative to the airbag before impacting it, which must be absorbed by the airbag. This effect serves to both increase the design strength requirements of the airbag and increase the injury induced in the occupant by the airbag. For these reasons, it would be desirable to have an airbag system that adjusts to the location of the occupant and which is designed so that the impact of the airbag causes little or no injury to the occupant.
It is conventional in the art that airbags contain orifices or vent holes for exhausting or venting the gas generated by the inflation means. Thus, typically within one second after the bag is inflated (and has provided its impact absorbing function), the gas has been completely exhausted from the bag through the vent holes. This imposes several limitations on the restraint system that encompasses the airbag system. T
Breed David S.
Sanders William Thomas
Automotive Technologies International Inc.
Jasmin Lynda
Rice Kenneth R.
Roffe Brian
LandOfFree
Tubular airbag, method of making the same and occupant... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tubular airbag, method of making the same and occupant..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tubular airbag, method of making the same and occupant... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2475007