Key Safety Systems, Inc.

Robert P Pettypiece, Jr

Tex K Monroe

Timothy Ilyes

John Fisher

An airbag assembly employs tape sensors to monitor the rate at which an airbag is deployed. The airbag is part of an airbag module that incorporates a vent that can be actuated if it is determined by logic associated with the airbag that the airbag has prematurely collided with an object. To better determine the dynamics of the airbag deployment, a sensor is positioned across a tear seam in the cover through which the airbag breaks. The sensor provides a direct indicator that the tear seam has opened, which is used as the starting time for monitoring the rate of airbag deployment. The tear seam sensor could also be used in conjunction with any airbag electronics to control a function of an airbag.

Airbag with tear seam sensor and deployment rate sensor

An airbag deployment sensor has a cartridge containing a quantity of tape one end of which is attached to the inside surface of an airbag cushion. Deployment of the cushion pulls tape from the cartridge at a rate that is monitored by transmitting light through the tape, or by detecting the presence of metalized, or magnetic shielding portions, of the tape.

Airbag deployment monitor and sensing electronics

A cartridge stores a quantity of string, one end of which is attached to the inside surface of an airbag cushion. A spool which transitions to a cone is situated within the cartridge. A narrow gap around the spool forms a string storage space and a similar gap overlies the cone and leads to an outlet. Positioned within the body of the cartridge is a light source and a light detector. As string is drawn out of the cartridge, the string traverses between the light sources and a light detector generating a signal directly proportional to the rate at which string is withdrawn. The geometry of the cartridge is arranged to provide friction against the string. The friction is created between the string and the junction between the cylindrical spool and the cone and rapidly overcomes the momentum of the string when the airbag cushion comes to a stop.

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Lakeland, FL, United States of America

Robert P Pettypiece, Jr