Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-11-16
2001-04-10
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S741000, C280S742000
Reexamination Certificate
active
06213503
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an inflator device including gas generators and more specifically to a dual level inflator which can selectively release gas at different rates and levels and thus enable an air bag or the like type of inflatable safety restraining device, to be deployed at different output levels in accordance with different sensor inputs.
2. Description of the Related Art
Recently, there has been a demand for controlling the rate and amount of inflation of safety devices such as air-bag restraint systems, in accordance with variables such as passenger size, position, seat belt usage and the velocity of a vehicle at time of collision.
In order to provide optimal occupant protection, different levels of output are required from the air bag inflator. For example, in a high speed collision with a large unbelted person, full rapid inflation of the air bag is required to provide the best restraint. In lower speed crashes with smaller size occupants or even out-of-position occupants, a lower, slower rate of inflation is required so as not to inadvertently injure the occupant but still provide enough inflation to provide restraint.
In order to achieve the two levels of inflation, it has been proposed in U.S. Pat. No. 3,773,353 to Trowbridge et al. to provide two separate charges and to ignite one in the event that a slow inflation is required and to ignite both in the event of a high speed collision, thus achieving the very rapid inflation and deployment of the air bag which is necessary under such circumstances. In this device the charges are arranged within a reservoir which is filled with a non-toxic gas under pressure. This housing is sealed by a burst plate that is punched out by a piston and rod type of arrangement when a first of the two charges is detonated. This arrangement however, suffers from the drawback of being relatively complex and therefore, relatively expensive. For example, no less than three burst plate arrangements are necessary. Also, the charges are each isolated from the reservoir and reservoir gas by an inner housing and a respective rupturable closure.
U.S. Pat. No. 3,905,515 to Allemann discloses another two-stage inflator assembly which utilizes two separate charges and which disposes the charge in a chamber which is used to store a non-noxious gas under pressure. However, this arrangement is even more complex than that in U.S. Pat. No. 3,773,353. In this arrangement a portion of the burst disc forms the head of a slidable shuttle valve member which is projectable into an exhaust passage to partially throttle the outflow of gases following a detonation of one or both of the two charges.
Consequently, there is a need for a cost effective, light-weight, compact, simple multi-level inflator for air bags and the like.
SUMMARY OF THE INVENTION
It is an object of the present invention, therefore, to overcome the disadvantages of the prior art and to provide a cost effective yet safe multi-level inflator device which effectively permits multi-level performance.
A further object of the present invention is to provide a multi-level inflator with two gas generators, which permits ignition of the generators, either separately, simultaneously or in a timed sequence to effect air bag inflation at different rates in accordance with sensor inputs resulting from a crash or the like.
It is a further object of the present invention to provide a multi-level inflator of the hybrid type including a pair of gas generators with pressure vessels connected to opposite sides of a center bulkhead or the like having separate outlets for each pressure vessel.
It is an additional object of the present invention to provide a multi-level inflator wherein the separate outlets are thrust neutral and are provided with burst discs or the like.
A further object of the present invention is to provide a multi-level inflator wherein the energetics packages are located at the outer ends of the pressure vessels and can be separately ignited.
A still further object of the present invention is to provide such a multi-level inflator wherein the bulkhead has additional openings therein to selectively connect the pressure vessels.
Still another object of the present invention is to provide a multi-level inflator which is simple in construction and easy to assemble to minimize the cost and size of the assembly.
These and other objects of the present invention are achieved by providing multi-level inflation device for inflating a vehicle safety restraint such as an air bag comprising a central bulkhead or the like, and a pair of generally cylindrical hybrid-type gas generator units having the pressure vessel portions thereof connected to opposite sides of the bulkhead which has a pair of gas outlets in separate communication with the pressure vessels through burst discs or the like. The energetics portions of the gas generator units are located on the outer ends thereof. There are additional openings in the bulkhead which serve to connect the pressure vessels of the gas generator units when desired. In this manner, the gas generating units may be activated separately, simultaneously or in a desired sequence through the initiation of one or both of the gas generator units.
REFERENCES:
patent: 5630619 (1997-05-01), Buchanan et al.
patent: 5794973 (1998-08-01), O'Loughlin et al.
Bilbrey David A.
Carlson Todd S.
Kohl Andrew C.
Renfroe Donald W.
Robbins Richard K.
Atlantic Research Corporation
Culbreth Eric
Nixon & Vanderhye PC
Presta Frank P.
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