Air bag inflator having helical gas floor space

• US 5,248,162 A
• Filed: 11/19/1991
• Issued: 09/28/1993
• Est. Priority Date: 11/19/1991
• Status: Expired due to Term

• 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: Corrion, Edward J., Husband, Clarence R., Braun, William P., Wallner, John P., Levosinski, George J.
• Primary Examiner(s): Tyson, Karin L.
• Application Number:
  US07/794,986
• Time in Patent Office: 679 Days
• Field of Search: 55/498, 55/486, 55/359, 210/483, 210/484, 210/489, 222/3, 280/736, 280/738, 280/740, 280/741, 280/742, 280/737, 422/164
• US Class Current: 280/740
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

An apparatus for inflating a vehicle occupant restraint such as an air bag comprises a source of gas for inflating the air bag. A filter is disposed outward of the gas source and has an outer surface. A pressure controlling member is spaced outward of the filter an encircles the gas source and the filter. A helical strand is interposed between the filter and the pressure controlling member to create a plenum between them. Gas supplied by the gas source accumulates in the gap until it builds up enough pressure to burst the pressure controlling member. The strand has a smooth cylindrical outer surface. Thus, any contact between the strand and the foil layer is line contact.

Claims

1. Apparatus for inflating a vehicle occupant restraint such as an air bag, said apparatus comprising:

a source of gas for inflating the vehicle occupant restraint;

a filter disposed outward of said source of gas and having an outer surface;

a pressure controlling member spaced outward of said filter; and

means for defining a plenum between said filter and said pressure controlling member, said plenum comprising a gas flow space through which gas from said source of gas can flow outward from said filter toward said pressure controlling member, said means including a plenum member having helical turns extending circumferentially entirely around said outer surface of said filter, a plurality of said helical turns being spaced from each other to define said gas flow space in a helical shape between said plurality of helical turns, said gas flow space having a continuous width extending axially between adjacent ones of said plurality of helical turns and having a continuous length extending circumferentially entirely around said outer surface of said filter a plurality of times with said plurality of helical turns;

said gas flow space being continuously open and free of obstructions between said plurality of helical turns through said width and length of said gas flow space to permit said gas to flow outward from said outer surface of said filter and radially through said gas flow space toward said pressure controlling member entirely across said width and entirely along said length of said gas flow space;

said plenum member being a strand consisting of a single continuous piece of wire wrapped around said outer surface of said filter, said strand having a substantially uniform diameter along its length and a substantially uniform thickness along its entire length, said thickness being substantially equal to the distance between said filter and said pressure controlling member.

2. Apparatus as defined in claim 1 wherein said pressure controlling member encircles said filter and said source of gas.

3. Apparatus as defined in claim 2 wherein said filter has a cylindrical outer surface, said apparatus further comprising a housing disposed outward of said filter, said housing comprising a cylindrical wall having inner and outer surfaces and means for defining a plurality of openings extending through said wall between said inner and outer surfaces.

4. Apparatus as defined in claim 3 wherein said pressure controlling member comprises an imperforate layer of foil disposed adjacent said inner surface of said cylindrical wall and having portions blocking said plurality of openings in said wall.

5. Apparatus comprising:

an inflatable vehicle occupant restraint;

a source of gas for inflating said vehicle occupant restraint;

a tubular cylindrical filter extending circumferentially around said source of gas;

a cylindrical wall member extending circumferentially around said filter, said wall member having gas flow openings for directing gas from said source of gas toward said vehicle occupant restraint;

a pressure controlling member located radially between said filter and said wall member, said pressure controlling member extending across said gas flow openings in said wall member; and

plenum means for defining a plenum between said filter and said pressure controlling member, said plenum comprising a gas flow space through which gas from said source of gas can flow outward from said filter toward said pressure controlling member, said plenum means having helical turns extending circumferentially entirely around said filter, a plurality of said helical turns being spaced from each other to define said gas flow space in a helical shape between said plurality of helical turns, said helically shaped gas flow space having a width extending axially between adjacent ones of said plurality of helical turns and having a length extending circumferentially entirely around said filter a plurality of times with said plurality of helical turns;

said helically shaped gas flow space being continuously open and free of obstructions between said plurality of helical turns throughout said width and length of said helically shaped gas flow space to permit said gas to flow outward from said filter and radially through said helically shaped gas flow space toward said pressure controlling member entirely across said width and entirely along said length of said helically shaped gas flow space;

said plenum means including a strand having helical turns extending circumferentially around said filter, said strand having a substantially uniform thickness extending along the length of said helical turns in said strand, said thickness being substantially equal to the distance between said filter and said pressure controlling member.

6. Apparatus as defined in claim 5 wherein said strand is disposed in helical line contact with said pressure controlling member, said helical line contact being coextensive with said length of said helical turns in said strand.

7. Apparatus as defined in claim 6 wherein said helical line contact is the only contact of said plenum means with said pressure controlling member radially between said filter and said pressure controlling member.

8. Apparatus comprising:

an inflatable vehicle occupant restraint;

a source of gas for inflating said vehicle occupant restraint;

a cylindrical wall member extending circumferentially around said source of gas, said wall member having gas flow openings for directing gas from said source of gas toward said vehicle occupant restraint;

a rupturable pressure controlling member extending circumferentially around the inside of said cylindrical wall member and across said gas flow openings;

filter means for filtering gas between said source of gas and said pressure controlling member, said filter means including a plurality of cylindrical layers of mesh filter screen extending around said source of gas between said source of gas and said pressure controlling member, one of said layers of mesh filter screen being closer to said pressure controlling member than any other layer of mesh filter screen between said source of gas and said pressure controlling member; and

plenum means for defining a plenum between said filter means and said pressure controlling member, said plenum means having a plurality of helical turns extending circumferentially entirely around said one of said mesh filter screens, said helical turns defining a gap extending around said one of said mesh filter screens in a helical shape between said helical turns, said gap defining a gas flow space through which gas can flow radially outward from said one of said mesh filter screens toward said pressure controlling member;

said plenum means including a strand having helical turns extending circumferentially around said one of said mesh filter screens, said strand having a substantially uniform thickness extending along the length of said helical turns in said strand, said thickness being substantially equal to the distance between said filter means and said pressure controlling member.

9. Apparatus as defined in claim 8 wherein said strand is disposed in helical line contact with said pressure controlling member, said helical line contact being coextensive with a plurality of said helical turns.

10. Apparatus as defined in claim 9 wherein said helical line contact is the only contact of said strand with said pressure controlling member radially between said filter means and said pressure controlling member.