POROUS DIFFUSER FOR GAS SUPPLY TO PASSENGER RESTRAINT

• US 3,853,332 A
• Filed: 03/31/1972
• Issued: 12/10/1974
• Est. Priority Date: 03/31/1972
• Status: Expired due to Term

• Current Assignee: HBB Limited Partnership
• Original Assignee: Robert W. Lynch
• Inventors: Lynch, Robert W.
• Primary Examiner(s): Betts, Kenneth H.
• Assistant Examiner(s): Silverstrim, John P.
• Application Number:
  US05/240,035
• Time in Patent Office: 984 Days
• Field of Search: 280/15AB 23/281 139/38
• US Class Current: 280/740
• CPC Class Codes: B60R 2021/2612 Gas guiding means, e.g. ducts
• CPC Class Codes: B60R 21/26 characterised by the inflation fluid source or means to control inflation fluid flow arrangement or mounting thereof to the vehicle B60R21/20; blasting cartridges for producing gas under pressure in general F42B3/04; initiators or igniters therefor F42B3/10
• CPC Class Codes: B60R 21/261 with means other than bag structure to diffuse or guide inflation fluid
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26

Abstract

A porous diffuser for an inflatable bag passenger restraint system for automobiles is provided between a supply of gas and the inflatable bag. In one embodiment it has a flow cross-section larger than the flow cross-section for gas at some other portion between the gas supply and the inflatable bag. In one embodiment the diffuser is arranged within the bag for cooling, filtering and distributing gas over a large area for avoiding damage to the bag and also for noise suppression. In another embodiment, the diffuser is between a pyrotechnic gas supply and a metering orifice for cooling and filtering the gas, thereby reducing pressure in the pyrotechnic gas generator. If desired the porous diffuser can serve as a flow limiting '"'"''"'"''"'"''"'"'orifice'"'"''"'"''"'"''"'"'.

Claims

1. In an improved inflatable bag passenger restraint system comprising a gas pyrotechnic generating composition, an inflatable passenger restraint bag, a flow limiting orifice through which gas from the pyrotechnic composition passes before entering the inflatable bag, the improvement comprising a porous diffuser through which substantially all of the gas passes between the pyrotechnic composition and the flow limiting orifice in the form of a hollow cylinder having its exterior in fluid communication with the pyrotechnic composition and its inside in fluid communication with the flow limiting orifice, and having a sufficient mass to reduce the temperature of the gases from the pyrotechnic composition to less than about 200*F at a point where the gases enter the bag.

2. A passenger restraint system comprising:

an inflatable passenger restraint bag;

a pressure resistant housing;

a propellant composition within the housing;

means for igniting the propellant composition;

a flow limiting orifice in fluid communication with the interior of the housing and with the interior of the bag; and

a porous diffuser in the gas flow path between the pyrotechnic composition and the flow limiting orifice and having a larger flow cross-section than the flow cross-section of the orifice in the form of a hollow cylinder having its outside surface in fluid communication with the propellant composition and its inside surface in fluid communication with the flow limiting orifice.

3. An automobile passenger restraint system comprising:

an inflatable passenger restraint bag;

a pressure resistant housing;

a pyrotechnic composition within the housing;

means for igniting the pyrotechnic composition;

a porous diffuser in the housing adjacent the pyrotechnic composition so that combustion gas from the pyrotechnic composition flows substantially unimpeded to the diffuser; and

a flow limiting orifice in fluid communication with the interior of the housing on the opposite side of the diffuser from the pyrotechnic composition and with the interior of the bag, said flow limiting orifice having a flow cross section less than the flow cross section of the diffuser; and

wherein the porous diffuser is in the form of a hollow cylinder of porous metal having its outside surface in direct fluid communication with the pyrotechnic composition and its inside surface in fluid communication with the flow limiting orifice.

4. An automobile passenger restraint system as defined in claim 3 wherein the porous metal has a mean pore size of about 65 microns.