Initiator for a gas generator

Abstract

An initiator employs ignition powder which can be manufactured easily, which can be handled safely, and which is stored in a cup of the initiator. Pins are inserted into and secured to holes of a header in the initiator. Distal end surfaces of the pins are flush with a distal end surface of the header; an insulative membrane is disposed so as to cover the distal end surface of one of the pins. When a high-voltage is applied between the pins, the membrane is destroyed and plasma is created. Further, when a subsequent low-voltage is applied between the pins, plasma is continuously generated. The ignition powder initiates its reaction by heat of the plasma.

1 . An initiator comprising: a casing containing ignition powder; an electrode; and an insulating layer disposed in the casing, wherein the insulating layer is in contact with the electrode on one surface and with the ignition powder on another surface, and wherein the initiator is configured so that reaction of the ignition powder is initiated by plasma generated by conducting electricity through the electrode.  
   
   
       2 . The initiator of  claim 1 , wherein the insulating layer comprises a synthetic resin or a glass fiber mold of about 10-300 μm in thickness.  
   
   
       3 . The initiator of  claim 1 , wherein the insulating layer is in the shape of a sheet and includes holes smaller than the grain diameter of the ignition powder.  
   
   
       4 . The initiator of  claim 1 , wherein the ignition powder comprises MgAl alloy powder; KCl0 3  powder; and silicon resin binder.  
   
   
       5 . The initiator of  claim 2 , wherein the ignition powder comprises MgAl alloy powder; KCl0 3  powder; and silicon resin binder.  
   
   
       6 . A method of activating an initiator including a casing containing ignition powder; an electrode; and an insulating layer disposed in the casing, wherein the insulating layer is in contact with the electrode on one surface and with the ignition powder on another surface, and wherein the initiator is configured so that reaction of the ignition powder is initiated by plasma generated by conducting electricity through the electrode, comprising the steps of: 
 applying a high voltage to the electrode to destroy the insulating layer; and subsequently    applying a low voltage to the electrode.    
   
   
       7 . The method of  claim 6 , wherein the step of applying the high voltage includes applying a voltage of at least about 1 kV.  
   
   
       8 . The method of  claim 7 , wherein the high voltage is applied for between about 0.1 μSec and about 50 μSec.  
   
   
       9 . The method of  claim 6 , wherein the step of applying a low voltage includes applying a voltage of between about 20 V and about 100 V.  
   
   
       10 . The method of  claim 9 , wherein the low voltage is applied for between about 50 μSec and about 1 mSec.  
   
   
       11 . A gas generator comprising: a gas generating agent; and an initiator for initiating gas generation reaction of the gas generating agent, wherein the initiator includes a casing containing ignition powder, an electrode, and an insulating layer disposed in the casing, wherein the insulating layer is in contact with the electrode on one surface and with the ignition powder on another surface, and wherein the initiator is configured so that reaction of the ignition powder is initiated by plasma generated by conducting electricity through the electrode.  
   
   
       12 . The gas generator of  claim 11 , wherein the insulating layer comprises a synthetic resin or a glass fiber mold of about 10-300 μm in thickness.  
   
   
       13 . The gas generator of  claim 11 , wherein the insulating layer is in the shape of a sheet and includes holes smaller than the grain diameter of the ignition powder.  
   
   
       14 . The gas generator of  claim 11 , wherein the ignition powder comprises MgAl alloy powder; KCl0 3  powder; and silicon resin binder.  
   
   
       15 . The gas generator of  claim 12 , wherein the ignition powder comprises MgAl alloy powder; KCl0 3  powder; and a silicon resin binder.  
   
   
       16 . A seatbelt apparatus comprising: 
 a seat belt, a tongue for connecting to a buckle, and a pretensioner,    wherein the pretensioner includes a gas generator and the gas generator includes a gas generating agent and an initiator for initiating gas generation reaction of the gas generating agent, the initiator including a casing containing ignition powder, an electrode; and an insulating layer disposed in the casing,    wherein the insulating layer is in contact with the electrode on one surface and with the ignition powder on another surface, and    wherein the initiator is configured so that reaction of the ignition powder is initiated by plasma generated by conducting electricity through the electrode.    
   
   
       17 . An airbag apparatus comprising: 
 an airbag and a gas generator;    wherein the gas generator includes a gas generating agent; and an initiator for initiating gas generation reaction of the gas generating agent;    wherein the initiator includes a casing containing ignition powder, an electrode; and an insulating layer disposed in the casing, and    wherein the insulating layer is in contact with the electrode on one surface and with the ignition powder on another surface, and wherein the initiator is configured so that reaction of the ignition powder is initiated by plasma generated by conducting electricity through the electrode.