Igniter for an inflatable occupant restraint

• US 5,002,308 A
• Filed: 01/18/1990
• Issued: 03/26/1991
• Est. Priority Date: 09/13/1988
• Status: Expired due to Fees

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Knowlden, Leo S., Lenzen, Reiner
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): Johnson, Brian L.
• Application Number:
  US07/467,806
• Time in Patent Office: 432 Days
• Field of Search: 280/728, 280/730, 280/731, 280/734, 280/735, 280/736, 280/741, 102/202.8, 102/210, 102/275.6
• US Class Current: 280/735
• CPC Class Codes: B60R 2021/335 Connections between collision detecting means and inflators using pyrothechnic transmission lines
• CPC Class Codes: B60R 21/01 Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents electrical circuits for transmission of signals between steering wheel and the vehicle itself B60R16/027; for electrically actuating belt retractor locking means B60R22/343
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558
• CPC Class Codes: B60R 21/017 including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves

Abstract

An igniter for use in a vehicle having gas generating material which upon ignition produces gas for inflating an inflatable occupant restraint. The igniter comprises a pyrotechnic transmission line having one end located adjacent the gas generating material. The pyrotechnic transmission line includes a housing and a plurality of pyrotechnic cords located in the housing and extending for substantially the length of the housing. A pair of electrically conductive members are located at a position spaced from the one end of the pyrotechnic transmission line. Each of the members have a portion disposed within the housing. The members are spaced apart. A spark is generated between the members to heat and thereby ignite the pyrotechnic cords in response to a sensor sensing deceleration of the vehicle at a rate above a predetermined rate of deceleration.

Claims

1. An apparatus for use in a vehicle having gas generating material which upon ignition produces gas for inflating an inflatable occupant restraint, said apparatus comprising:

a pyrotechnic transmission line having one end located adjacent the gas generating material, said pyrotechnic transmission line including a housing and a plurality of pyrotechnic cords located in said housing and extending for substantially the length of said housing, said plurality of pyrotechnic cords igniting upon the application of heat thereto;

a pair of electrically conductive members located at a position spaced from said one end of said pyrotechnic transmission line, each of said members having a portion located within said housing, said portions of said members being spaced apart, and said plurality of pyrotechnic cords being located between said portions; and

a piezoelectric crystal operatively connected with said members to generate a spark between said members to ignite said pyrotechnic cords in response to a force exceeding a predetermined force being applied to said piezoelectric crystal.

2. The apparatus set forth in claim 1 wherein said electrodes are disposed in a plane extending transversely of the longitudinal central axis of said pyrotechnic transmission line.

3. An apparatus for igniting material said apparatus comprising:

a pyrotechnic transmission line having one end located adjacent the material, said pyrotechnic transmission line including a housing and a plurality of pyrotechnic cords located in said housing and extending for substantially the length of said housing, said plurality of pyrotechnic cords igniting upon the application of heat thereto;

a pair of electrically conductive members located at a position spaced from said one end of said pyrotechnic transmission line, each of said members having a portion located within said housing, said portions of said members being spaced apart, and said plurality of pyrotechnic cords being located between said portions, and

means for generating a spark between said pair of members to heat and thereby ignite said plurality of pyrotechnic cords;

said means for generating a spark including a piezoelectric crystal operatively connected with said pair of members to generate the spark between said pair of members in response to a force exceeding a predetermined force being applied to said piezoelectric crystal.

4. An apparatus for igniting material, said apparatus comprising:

a pyrotechnic transmission line having one end located adjacent the material, said pyrotechnic transmission line including a housing and a plurality of pyrotechnic cords located in said housing and extending for substantially the length of said housing, said plurality of pyrotechnic cords igniting upon the application of heat thereto;

an electrically conductive member located at a position spaced from said one end of said pyrotechnic transmission line and within said housing;

an electrode located within said pyrotechnic transmission line at a position spaced from said one end of said pyrotechnic transmission line and spaced from said electrically conductive member, and said plurality of pyrotechnic cords being located between said electrically conductive member and said electrode; and

means for generating a spark between said electrode and said electrically conductive member to ignite said plurality of pyrotechnic cords;

wherein said means for generating a spark further includes an actuatable sensor and a power source operatively connected with said electrode and said member to generate a spark between said electrode and said member in response to actuation of said sensor;

said power source comprising a piezoelectric crystal which generates a spark when a force exceeding a predetermined force is applied to said piezoelectric crystal.

5. An apparatus for igniting material for use in a vehicle having gas generating material, said gas generating material upon ignition producing gas for inflating an inflatable occupant restraint, said apparatus comprising:

a pyrotechnic transmission line having one end located adjacent the material, said pyrotechnic transmission line including a housing and a plurality of pyrotechnic cords located in said housing and extending for substantially the length of said housing, said plurality of pyrotechnic cords igniting upon the application of heat thereto;

a pair of electrically conductive members located at a position spaced from said one end of said pyrotechnic transmission line, each of said members having a portion located within said housing, said portions of said members being spaced apart, and said plurality of pyrotechnic cords being located between said portions;

means for generating a spark between said pair of members to heat and thereby ignite said plurality of pyrotechnic cords;

said means for generating a spark including a power source, said vehicle having a vehicle electrical system and said power source being independent of the vehicle electrical system.

6. The apparatus of claim 5 wherein said power source includes a means which in response to a force undergoes deformation for generating an electrostatic charge.

7. The apparatus of claim 6 wherein said means for generating an electrostatic charge includes a piezoelectric crystal operatively connected with said pair of members to generate a spark between said pair of members in response to a force exceeding a predetermined force being applied to said piezoelectric crystal.

8. The apparatus set forth in claim 5 wherein one of said pair of members comprises a tubular metal sleeve located coaxially in said housing and the other of said pair of members is located coaxially within said sleeve.

9. The apparatus set forth in claim 5 wherein said housing comprises a flexible tubular member, said pyrotechnique transmission line comprising a plurality of said pyrotechnique cords located in said housing and said plurality of pyrotechnique cords burning by deflagration upon ignition and at a rate that increases as said plurality of pyrotechnique cords burn.

10. The apparatus set forth in claim 5 wherein each of said pair of members comprises an elongated rod-like electrode, each of said electrodes having an end portion located within said housing, the end portion of one of said electrodes being spaced from the (an) end portion of the other of said electrodes.

11. The apparatus set forth in claim 10 wherein said electrodes are disposed in a plane extending transversely of the longitudinal central axis of said pyrotechnique transmission line.

12. The apparatus set forth in claim 5 wherein one of said members is a tubular metal sleeve and wherein the other said members is an electrode located coaxially relative to said sleeve and further including an insulator disposed around a portion of said electrode for electrically insulating said electrode from said sleeve.