Air bag inflator

• US 6,672,616 B2
• Filed: 03/14/2002
• Issued: 01/06/2004
• Est. Priority Date: 03/15/2001
• Status: Expired due to Fees

• Current Assignee: Autoliv Development AB (Autoliv Incorporated)
• Original Assignee: Autoliv AB (Autoliv Incorporated)
• Inventors: Ericsson, Dan, Jonsson, Jan
• Primary Examiner(s): English, Peter C.
• Application Number:
  US10/097,122
• Publication Number:
  US 20020130502A1
• Time in Patent Office: 663 Days
• Field of Search: 280/737, 280/736, 280/741, 280/742, 137/68.13, 137/68.3, 137/62.29
• US Class Current: 280/737
• CPC Class Codes: B60R 21/264 using instantaneous generation of gas, e.g. pyrotechnic B60R21/268 takes precedence
• CPC Class Codes: Y10T 137/1647 Explosive actuation
• CPC Class Codes: Y10T 137/1767 Movable knife or cutter

Abstract

An inflator for an air-bag has two gas chambers mounted on a central block (1). The central block defines passages leading from the gas chambers to the air-bag, but the passages are initially sealed by closures . An ignitor mounted on the block can generate hot gas to move an actuating element in a predetermined direction, the actuating element having a conical face which acts on inclined faces of two opening elements which are thus moved apart to rupture the closures to permit gas to flow from the chambers into the air-bag. Finally gas from the ignitor can also flow through a passage into the air-bag to ignite the mixed gases from the two gas chambers.

Claims

1. An inflator for an air-bag, the inflator comprising a first gas chamber for containing a first gas, and a second gas chamber for containing a second gas, each gas chamber being mounted on a central block or housing, the central block or housing defining gas flow passages leading from each gas chamber to direct gas to an air-bag, each passage initially being closed by a closure, the block or housing containing an opening element associated with each closure, adapted to move from an initial position in which integrity of the associated closure is maintained to a final position in which the associated closure is opened, there being an igniter to generate hot gas, and an actuating element adapted to be moved in response to the generation of the hot gas, means being provided to constrain the actuating element to move in a predetermined direction over at least part of its movement, the actuating element acting upon the opening elements to move the opening elements substantially simultaneously to open the closures to permit (1) gas to flow from the gas chambers through the gas flow passages, (2) movement of the actuating element and the opening elements over a predetermined distance, and (3) opening a further gas flow path to permit gas from the igniter to flow through the further gas flow path into the air-bag.

2. An inflator according to claim 1 wherein said gas flow passages comprises two gas flow passages, each passage extending from a central part of the block or housing to a respective one of said closures, each passage containing a respective one of said opening elements, the actuating element being adapted, on movement in response to the generation of hot gas, to engage and act on part of each of said opening elements to cause the opening elements to move substantially simultaneously to open the closures.

3. An inflator according to claim 2 wherein each opening element comprises a head defining an end face and wherein the actuating element includes surfaces adapted to engage with said end faces, either the end faces or the surfaces, or both the end faces and the surfaces, being inclined with respect to axes of the passages to provide a wedging effect.

4. An inflator according to claim 3 wherein the head of each opening element is provided with an inclined planar face, and the actuating element is of substantially conical form.

5. An inflator according to claim 4 wherein the conical form of the actuating element is provided with a plurality of cut-outs.

6. An inflator according to claim 2 wherein a separate respective gas flow duct is provided extending from each of said passages to form a gas flow path from each passage to the interior of the air-bag.

7. An inflator according to claim 1 wherein the actuating element is provided with an axially extending skirt, the axially extending skirt initially being received in an annular passage, the skirt and the annular passage co-operating to constrain the actuating element to move in said predetermined direction.

8. An inflator according to claim 1 wherein the first gas chamber contains an oxidisable gas, alone or in admixture with an inert gas, and wherein the second gas chamber contains an oxidising gas, alone or in combination with an inert gas.

9. An inflator according to claim 8 wherein the oxidisable gas is methane, ethane, propane, acetylene, hydrogen or mixtures thereof.

10. An inflator according to claim 8 wherein the oxidising gas is oxygen or an oxide of nitrogen.

11. An inflator according to claim 8 wherein each inert gas is argon or helium or a mixture thereof.

12. An inflator according to claim 1 wherein each closure is in the form of a breakable foil.