Sequenced orifice fluid supply for occupant restraint system

• US 3,966,228 A
• Filed: 01/31/1975
• Issued: 06/29/1976
• Est. Priority Date: 08/04/1972
• Status: Expired due to Term

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Neuman, Richard F.
• Primary Examiner(s): Wood, Jr., M. H.
• Assistant Examiner(s): Silverstrim, John P.
• Application Number:
  US05/546,060
• Time in Patent Office: 515 Days
• Field of Search: 280/150 AB, 222/3, 137/67, 137/68, 137/1, 137/71
• US Class Current: 280/737
• CPC Class Codes: B60R 2021/2612 Gas guiding means, e.g. ducts
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/261 with means other than bag structure to diffuse or guide inflation fluid
• CPC Class Codes: B60R 21/268 using instantaneous release of stored pressurised gas B60R21/26005 takes precedence
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators
• CPC Class Codes: Y10T 137/1789 Having pressure responsive valve

Abstract

An occupant restraint system for a vehicle including an air bag having a collapsed inoperative condition and an expanded operative condition for restraining movement of an occupant of the vehicle during a collision, a fluid supply, and a diffuser for directing fluid from the fluid supply into the air bag. The fluid supply includes a staged source of fluid for expanding the air bag. Fluid from the first source stage is introduced into the diffuser immediately upon the collision of the vehicle to initiate expansion of the air bag. After a time delay of milliseconds, a greater mass flow of fluid from the second source stage is introduced into the diffuser to complete the expansion of the air bag.

Claims

1. A fluid supply for an occupant restraint system having:

a confinement having a collapsed inoperative condition and an expanded operative condition for restraining movement of an occupant of a vehicle during a collision, said fluid supply comprising;

means for directing fluid into the confinement;

a vessel defining first and second pressure chambers fluidically in series;

gas under pressure in the first and second pressure chambers;

means substantially blocking fluid flow between said first and second chambers;

means for directing an initial flow of the gas from the first chamber into the fluid directing means to effect an initial expansion of the confinement; and

means for subsequently removing said blocking means and directing a flow of the gas from the second chamber through the first chamber and into the fluid directing means to effect full expansion of the confinement after the confinement has been initially expanded.

2. An occupant restraint system according to claim 1 herein:

the mass of gas in the first chamber is less than the mass of gas in the second chamber;

the mass of gas in the first and second chambers is greater than the mass of gas needed to expand the confinement; and

the mass of gas needed to expand the confinement is greater than the mass of gas in the first chamber.

3. A fluid supply according to claim 1 wherein:

the vessel further defines a first opening communicating the first chamber with the fluid directing means and a second opening communicating the first chamber with the second chamber;

the means for directing the flow of the fluid from the first chamber comprises

a. a first means sealing the first opening, and

b. means operable in response to a collision signal to unseal the first sealing means; and

said blocking means comprises rupturable orifice means and said removing means comprises the pressure difference between said first and second chambers created by said initial flow, whereby said rupturable orifice means in ruptured to change from a size initially substantially restricting fluid flow to a size permitting substantially greater flow.

4. A fluid supply for use with an occupant restraint system including a confinement having a collapsed inoperative condition and an expanded operative condition for restraining movement of an occupant of a vehicle during a collision and means for directing fluid into the confinement, the fluid supply comprising:

a source of fluid including first and second pressure chambers occupied by fluid and arranged fluidically in series;

first means operative to direct an initial flow of fluid from the first chamber to the fluid directing means to effect an initial expansion of the confinement; and

second means operative to subsequently direct fluid from said second chamber to said first chamber permitting a secondary fluid flow at a rate greater than said initial flow to the fluid directing means such that said initial and secondary fluid flows are combined to effect further expansion of the confinement after the confinement has been initially expanded.

5. A fluid supply according to claim 4 wherein said first means comprises a first opening communicating said first chamber with said fluid directing means, a first rupture disk sealing said first opening, and means to rupture said first rupture disk;

and said second means comprises a second opening communicating said second chamber with said first chamber, a second rupture disk normally blocking said second opening, said second rupture disk rupturing subsequently to said first rupture disk, and a passage in said second rupture disk having a cross sectional area that is substantially less than the cross sectional area of said first opening, whereby pressure in said first and second chambers is equivalized prior to rupture of said first rupture disk.

6. A fluid supply for a vehicle occupant restraint system of the type having an inflatable confinement and means responsive to a collision to inflate said confinement, said fluid supply comprising:

a. a source of pressurized fluid including reservoir means containing a predetermined amount of fluid under pressure;

b. means operable to direct fluid flow from said source;

c. means operable to activate said fluid source and release fluid from said reservoir means;

d. two-stage means including a first chamber within said reservoir means connected to discharge fluid to said directing means and a second chamber within said reservoir means and arranged fluidically in series with said first chamber, said two-stage means being responsive to said activation means and operable to permit a first stage flow of fluid from said first chamber, having a predetermined maximum mass flow rate to said directing means and operable to subsequently permit a second stage flow from said second chamber, through said first chamber, having a second predetermined maximum mass flow rate occurring subsequent to said first stage maximum mass flow rate, said second stage maximum being greater than said first stage maximum.

7. The fluid supply defined in claim 6 wherein said two-stage means includes rupturable means disposed in the flow path intermediate said first and second fluid chambers, said rupturable means being operable to initially substantially restrict release of fluid from said second chamber and, upon loss of fluid in said first chamber, said rupturable means being ruptured to permit a substantially greater flow of fluid from said second chamber.

8. The fluid supply defined in claim 7, wherein said activating means includes electroexplosive means.

9. The fluid supply defined in claim 7, wherein said rupturable means includes a disk responsive upon loss of fluid in said first chamber to the pressure differential between said first and second chambers.

10. The fluid supply defined in claim 6, wherein said reservoir means includes an exit passage communicating said first chamber with said fluid directing means and a second passage communicating said second chamber with said first chamber and said two-stage means includes rupturable means disposed in said second passage, said rupturable means being operable to release fluid from said second chamber upon loss of fluid in said first chamber.

11. The fluid supply defined in claim 10, wherein said rupturable means includes a bleed orifice such that the fluid pressure in said first and second chambers is equalized prior to release of fluid from said first chamber.